Mattermost Server
Monthly
Incorrect authorization in Mattermost Boards allows an authenticated board editor to relink any editable board to an arbitrary channel by exploiting a missing PermissionManageBoardRoles check on the channelId field of the batch endpoint. Affected are Mattermost versions 11.7.x through 11.7.6, 10.11.x through 10.11.21, and 11.8.x through 11.8.3 (advisory MMSA-2026-00686). No public exploit code or CISA KEV listing has been identified at time of analysis, but the low attack complexity and network accessibility make this straightforward to execute for any authenticated board editor.
Incorrect authorization in Mattermost's Boards component across versions 11.7.x through 11.7.6, 10.11.x through 10.11.21, and 11.8.x through 11.8.3 enables privilege escalation within board management. Board editors and non-guest team members can supply arbitrary values in BoardMember.Scheme* fields through the boards member API or archive-import endpoint, effectively granting board admin rights to any user without server-side enforcement. No public exploit has been identified at time of analysis, and the vulnerability is not listed in the CISA KEV catalog.
Denial of service in Mattermost's Boards (focalboard) plugin allows any authenticated user to crash the plugin process and disrupt Boards availability for all users on the instance by sending a single malformed WebSocket message. The root cause is absent input validation on the teamId field type in custom_focalboard_SUBSCRIBE_TEAM WebSocket commands, classified under CWE-704 (Incorrect Type Conversion). Affected versions span 11.7.x through 11.7.6, 10.11.x through 10.11.21, and 11.8.x through 11.8.3; no public exploit has been identified at time of analysis.
Privilege escalation in Mattermost's channel administration API allows authenticated channel administrators to assign non-channel-scoped roles to channel members, exceeding their intended authorization boundary. Three active release lines are affected: 10.11.x through 10.11.21, 11.7.x through 11.7.6, and 11.8.x through 11.8.2. No public exploit code has been identified at time of analysis, and the vulnerability is not listed in the CISA KEV catalog.
Private channel membership disclosure in Mattermost's Boards feature allows any authenticated team member to enumerate who belongs to private channels they are not authorized to view. Affected across three concurrently maintained release trains - 11.7.x through 11.7.6, 10.11.x through 10.11.21, and 11.8.x through 11.8.3 - the flaw is exploitable by any valid team account via standard board management API calls. No public exploit or active exploitation has been identified at time of analysis; the CVSS score of 4.3 (PR:L, C:L) accurately reflects the limited but real confidentiality impact, particularly meaningful in regulated environments where private channel membership itself is sensitive.
Mattermost's Playbooks feature in versions 11.7.x through 11.7.6 and 10.11.x through 10.11.21 omits run-state enforcement on API write operations, allowing any authenticated run participant to alter completed playbook runs via REST and GraphQL endpoints. An attacker with low privileges can overwrite status, checklists, retrospective content, ownership, and participant lists on runs that should be immutable once finished, undermining post-incident audit integrity. No public exploit has been identified at time of analysis, and the vulnerability is not listed in the CISA KEV catalog.
Incorrect authorization in Mattermost's OAuth and personal access token management endpoints allows an OAuth application holding a delegated user token to call account-management endpoints beyond its intended scope, revoking the victim user's authorizations or tokens for unrelated integrations. Affected are Mattermost 11.7.0 through 11.7.6 and 10.11.0 through 10.11.21. No public exploit code has been identified and this vulnerability is not listed in the CISA KEV catalog, though the low-complexity, network-accessible nature of the flaw makes it straightforward to abuse for any actor who has legitimately obtained an OAuth delegated token.
Privilege escalation in Mattermost's Boards feature allows a low-privileged board member to elevate a guest user to Board Admin by importing a specially crafted .boardarchive file. Affected are Mattermost versions 10.11.0 through 10.11.21 and 11.7.0 through 11.7.6. No public exploit or KEV listing has been identified, but the low attack complexity and the insider-threat profile make this a meaningful risk in multi-tenant or externally-collaborative Mattermost deployments.
Incorrect authorization in Mattermost's ABAC policy unassign API endpoint allows an authenticated team administrator to remove attribute-based access control policy assignments from channels that no longer belong to their team. Affected releases are Mattermost 11.7.0 through 11.7.6 and 11.8.0 through 11.8.3, tracked as MMSA-2026-00718 (ENISA EUVD-2026-60212). The exploit window opens when a channel is migrated between teams and the endpoint fails to re-verify team membership before executing the unassignment, letting a malicious admin modify access-control policy state beyond their administrative boundary.
Privilege retention in Mattermost Boards allows a user demoted to System Guest to continue exercising Board Admin privileges via the Boards REST API or UI. Affected are Mattermost versions 11.7.0-11.7.6, 10.11.0-10.11.21, and 11.8.0-11.8.3, where the SchemeAdmin flag is not reconciled against the user's current role during or after demotion. An authenticated attacker in this state can invoke admin-only Boards operations - including modifying board permissions and settings - without detection by role-based access checks. No public exploit code is identified and no CISA KEV listing is present at time of analysis.
Server-side request forgery in the Mattermost Agents plugin MCP server (stdio mode) allows a low-privileged local attacker to make the server fetch arbitrary internal URLs submitted as file attachment references in post creation requests, enabling exfiltration of data from RFC 1918-addressed services on the internal network. Affected are Mattermost deployments running versions 10.11.x ≤ 10.11.18, 11.5.x ≤ 11.5.6, and 11.6.x ≤ 11.6.3 with the Agents plugin's MCP server active in stdio mode. No public exploit code or CISA KEV listing is present in the available data; exploitation is constrained to attackers who already have local access to the stdio MCP interface.
Markdown image rendering restrictions in Mattermost are bypassed specifically for AI bot tool result posts, enabling authenticated attackers to exfiltrate data to attacker-controlled infrastructure. Affected are Mattermost versions 10.11.x through 10.11.18, 11.5.x through 11.5.6, and 11.6.x through 11.6.3. When a victim's client renders an AI bot tool result post containing injected markdown image syntax, the client issues an outbound request to the attacker's server, leaking request metadata such as session tokens or channel context. No public exploit code exists and this vulnerability is not listed in the CISA KEV catalog at time of analysis.
Mattermost Server versions 11.3.0, 11.2.x through 11.2.2, and 10.11.x through 10.11.10 contain a server-side request forgery (SSRF) vulnerability due to improper validation of IPv4-mapped IPv6 addresses, allowing authenticated attackers to bypass reserved IP restrictions and access internal services. An attacker with login credentials can craft requests using IPv6 notation (such as [::ffff:127.0.0.1]) to reach localhost or other restricted internal endpoints that would normally be blocked. No patch is currently available for this vulnerability.
A remote code execution vulnerability (CVSS 4.3) that allows guest users without read permissions. Remediation should follow standard vulnerability management procedures.
CVE-2026-22545 is a security vulnerability (CVSS 3.1) that allows an authenticated attacker. Remediation should follow standard vulnerability management procedures.
CVE-2026-21386 is a security vulnerability (CVSS 4.3) that allows an authenticated team member. Remediation should follow standard vulnerability management procedures.
Mattermost versions 10.11.x <= 10.11.9 fail to enforce invite permissions when updating team settings, which allows team administrators without proper permissions to bypass restrictions and add users to their team via API requests. Mattermost Advisory ID: MMSA-2025-00561 [CVSS 3.8 LOW]
Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 fail to properly validate team membership when processing channel mentions which allows authenticated users to determine the existence of teams and their URL names via posting channel shortlinks and observing the channel_mentions property in the API response. [CVSS 4.3 MEDIUM]
Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 fail to sanitize sensitive data in WebSocket messages which allows authenticated users to exfiltrate password hashes and MFA secrets via profile nickname updates or email verification events. [CVSS 5.7 MEDIUM]
Mattermost Server versions 11.1.x through 11.1.2, 10.11.x through 10.11.9, and 11.2.x through 11.2.1 inadequately enforce login method restrictions, permitting authenticated users to circumvent SSO-only requirements by authenticating with a userID instead. This allows an attacker with valid credentials to gain unauthorized access to accounts restricted to single sign-on authentication. No patch is currently available for this vulnerability.
Insufficient identity validation in Mattermost Server (versions 11.1.x through 11.2.1 and earlier) and Zoom Plugin (versions up to 1.11.0) allows authenticated users to initiate Zoom meetings as arbitrary users and modify other users' posts through direct API manipulation. An attacker with valid credentials can exploit the /api/v1/askPMI endpoint to impersonate other users and alter post content without proper authorization checks. The vulnerability affects multiple Mattermost and plugin versions with no patch currently available.
Mattermost and Zoom plugin versions fail to properly authenticate users before allowing modifications to Zoom meeting restrictions, enabling any logged-in user to alter meeting settings across arbitrary channels. Affected versions include Mattermost 11.1.x through 11.1.2, 10.11.x through 10.11.9, 11.2.x through 11.2.1, and Zoom plugin versions up to 1.11.0. No patch is currently available for this privilege escalation vulnerability.
Mattermost versions 11.1.2, 10.11.9, and 11.2.1 and earlier fail to properly enforce access controls in the Jira plugin's /create-issue API endpoint, allowing authenticated users to read restricted post content and attachments from channels they cannot access by referencing post IDs. An attacker with Jira plugin access can exploit this to enumerate and exfiltrate sensitive information from private or restricted channels. No patch is currently available for affected versions.
Mattermost versions 10.11.x <= 10.11.9 fail to properly validate channel membership at the time of data retrieval which allows a deactivated user to learn team names they should not have access to via a race condition in the /common_teams API endpoint.. Mattermost Advisory ID: MMSA-2025-00549 [CVSS 3.1 LOW]
Mattermost versions 10.11.x <= 10.11.8, 11.1.x <= 11.1.1, 11.0.x <= 11.0.6 fail to prevent infinite re-renders on API errors which allows authenticated users to cause application-level DoS via triggering unbounded component re-render loops. [CVSS 6.8 MEDIUM]
Mattermost versions 10.11.x <= 10.11.8 fail to validate input size before processing hashtags which allows an authenticated attacker to exhaust CPU resources via a single HTTP request containing a post with thousands space-separated tokens [CVSS 3.1 LOW]
Mattermost versions 11.0.x <= 11.0.2, 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12 fail to validate user permissions when deleting comments in Boards, which allows an authenticated user with the editor role to delete comments created by other users.
Mattermost versions 11.0.x <= 11.0.2, 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12 fail to to verify that the token used during the code exchange originates from the same authentication. Rated critical severity (CVSS 9.9), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 11.0.x <= 11.0.2, 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12 fail to sanitize team email addresses to be visible only to Team Admins, which allows any authenticated. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12, 11.0.x <= 11.0.3 fail to properly validate OAuth state tokens during OpenID Connect authentication which allows an. Rated critical severity (CVSS 9.9), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.11.x <= 10.11.3, 10.5.x <= 10.5.11 fail to enforce access permissions on the Agents plugin which allows other users to determine when users had read channels via channel member. Rated low severity (CVSS 3.0), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.11.x <= 10.11.3, 10.5.x <= 10.5.11, 10.12.x <= 10.12.0 fail to sanitize user data which allows system administrators to access password hashes and MFA secrets via the POST. Rated medium severity (CVSS 4.9), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.11.x <= 10.11.3, 10.5.x <= 10.5.11, 10.12.x <= 10.12.0 fail to validate the relationship between the post being updated and the MSTeams plugin OAuth flow which allows an. Rated medium severity (CVSS 5.4), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions <11 fail to enforce multi-factor authentication on WebSocket connections which allows unauthenticated users to access sensitive information via WebSocket events. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions <11.0 fail to properly enforce the "Allow users to view archived channels" setting which allows regular users to access archived channel content and files via the "Open in. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions <11 fail to properly restrict access to archived channel search API which allows guest users to discover archived public channels via the. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.11.x <= 10.11.3, 10.5.x <= 10.5.11 fail to properly validate team membership permissions in the Add Channel Member API which allows users from one team to access user metadata. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.8, 9.11.x <= 9.11.17 fail to properly validate access controls which allows any authenticated user to download sensitive files via board file download endpoint. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.10.x <= 10.10.1, 10.9.x <= 10.9.3 fail to validate import directory path configuration which allows admin users to. Rated high severity (CVSS 8.0), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.9 fail to properly validate redirect URLs which allows attackers to redirect users to malicious sites via crafted OAuth login URLs. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
Mattermost versions 10.10.x <= 10.10.1, 10.5.x <= 10.5.9, 10.9.x <= 10.9.4 fail to validate the redirect_to parameter, allowing an attacker to craft a malicious link that, once a user authenticates. Rated high severity (CVSS 7.6), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.10.x <= 10.10.1, 10.9.x <= 10.9.3 fail to properly validate cache keys for link metadata which allows authenticated users. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.10.x <= 10.10.1 fail to properly sanitize user data during shared channel membership synchronization, which allows malicious or compromised remote clusters to access sensitive. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.10.x <= 10.10.0, 10.9.x <= 10.9.3 fail to validate import data which allows a system admin to crash the server via the. Rated medium severity (CVSS 4.9), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 10.10.x <= 10.10.0, 10.9.x <= 10.9.3 fail to sanitize file names which allows users with file upload permission to overwrite file attachment. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.9.x <= 10.9.2 fails to sanitize path traversal sequences in template file destination paths, which allows a system admin. Rated medium severity (CVSS 6.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.8, 9.11.x <= 9.11.17 fail to properly validate authorization for team scheme role modifications which allows Team Admins to demote Team Members to Guests via the. Rated low severity (CVSS 3.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.8 fail to validate access controls at time of access which allows user to read a thread via AI posts. Rated low severity (CVSS 3.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.9.x <= 10.9.2, 10.10.x <= 10.10.0 fail to validate upload types in remote cluster upload sessions which allows a system. Rated medium severity (CVSS 6.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.9.x <= 10.9.2 fail to sanitize the team invite ID in the POST /api/v4/teams/:teamId/restore endpoint which allows an team. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost Server versions 10.5.x <= 10.5.9 utilizing the Agents plugin fail to reject empty request bodies which allows users to trick users into clicking malicious links via post actions. Rated low severity (CVSS 3.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.9.x <= 10.9.1, 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17 fail to properly validate file paths during plugin import operations which allows restricted admin users to. Rated medium severity (CVSS 6.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.5, 9.11.x <= 9.11.15, 10.8.x <= 10.8.0, 10.7.x <= 10.7.2, 10.6.x <= 10.6.5 fail to properly validate channel membership when retrieving playbook run metadata, allowing authenticated users who are playbook members but not channel members to access sensitive information about linked private channels including channel name, display name, and participant count through the run metadata API endpoint.
Mattermost versions 10.5.x <= 10.5.5, 9.11.x <= 9.11.15, 10.8.x <= 10.8.0, 10.7.x <= 10.7.2, 10.6.x <= 10.6.5 fail to properly enforce channel member management permissions when adding participants to playbook runs. This allows authenticated users with member-level permissions to bypass system admin restrictions and add or remove users to/from private channels via the playbook run participants feature, even when the 'Manage Members' permission has been explicitly removed. This can lead to unauthorized access to sensitive channel content and allow guest users to gain channel management privileges.
Mattermost versions 10.5.x <= 10.5.5, 9.11.x <= 9.11.15, 10.8.x <= 10.8.0, 10.7.x <= 10.7.2, 10.6.x <= 10.6.5 fail to properly retrieve requestorInfo from playbooks handler for guest users which allows an attacker access to the playbook run.
Mattermost versions 10.5.x <= 10.5.5, 9.11.x <= 9.11.15, 10.8.x <= 10.8.0, 10.7.x <= 10.7.2, 10.6.x <= 10.6.5 fail to properly enforce channel member management permissions in playbook runs, allowing authenticated users without the 'Manage Channel Members' permission to add or remove users from public and private channels by manipulating playbook run participants when the run is linked to a channel.
A remote code execution vulnerability (CVSS 9.9) that allows authenticated users. Critical severity with potential for significant impact on affected systems.
Mattermost versions 10.7.x <= 10.7.1, 10.6.x <= 10.6.3, 10.5.x <= 10.5.4, 9.11.x <= 9.11.13 fail to properly validate LDAP group ID attributes, allowing an authenticated administrator with PermissionSysconsoleWriteUserManagementGroups permission to execute LDAP search filter injection via the PUT /api/v4/ldap/groups/{remote_id}/link API when objectGUID is configured as the Group ID Attribute.
Mattermost versions 10.7.x <= 10.7.0, 10.5.x <= 10.5.3, 9.11.x <= 9.11.12 fails to properly enforce access control restrictions for System Manager roles, allowing authenticated users with System. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.7.x <= 10.7.0, 10.6.x <= 10.6.2, 10.5.x <= 10.5.3, 9.11.x <= 9.11.12 fails to properly invalidate personal access tokens upon user deactivation, allowing deactivated users to. Rated medium severity (CVSS 5.4), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.7.x <= 10.7.0, 10.6.x <= 10.6.2, 10.5.x <= 10.5.3, 9.11.x <= 9.11.12 fail to clear Google OAuth credentials when converting user accounts to bot accounts, allowing attackers to. Rated medium severity (CVSS 4.2), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.7.x <= 10.7.0, 10.5.x <= 10.5.3, 9.11.x <= 9.11.12 fail to properly enforce access controls for guest users accessing channel member information, allowing authenticated guest. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.7.x <= 10.7.0, 10.6.x <= 10.6.2, 10.5.x <= 10.5.3, 9.11.x <= 9.11.12 fail to properly validate permissions when changing team privacy settings, allowing team administrators. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.3, 9.11.x <= 9.11.11 fail to check `RestrictSystemAdmin` setting if user doesn't have access to `ExperimentalSettings` which allows a System Manager to access. Rated low severity (CVSS 2.7), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.2, 9.11.x <= 9.11.11 failed to properly verify a user's permissions when accessing groups, which allows an attacker to view group information via an API request. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.6.x <= 10.6.1, 10.5.x <= 10.5.2, 10.4.x <= 10.4.4, 9.11.x <= 9.11.11 fail to check the correct permissions which allows authenticated users who only have permission to invite. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.6.x <= 10.6.1, 10.5.x <= 10.5.2, 10.4.x <= 10.4.4, 9.11.x <= 9.11.11 fail to lockout LDAP users following repeated login failures, which allows attackers to lock external LDAP. Rated medium severity (CVSS 5.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Mattermost versions 10.4.x <= 10.4.2, 10.5.x <= 10.5.0, 9.11.x <= 9.11.10 fail to properly validate permissions for the API endpoint /plugins/playbooks/api/v0/signal/keywords/ignore-thread, allowing. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.4.x <= 10.4.2, 10.5.x <= 10.5.0, 9.11.x <= 9.11.10 fail to properly validate the props used by the RetrospectivePost custom post type in the Playbooks plugin, which allows an. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.4.x <= 10.4.2, 10.5.x <= 10.5.0, 9.11.x <= 9.11.10 fail to validate the uniqueness and quantity of task actions within the UpdateRunTaskActions GraphQL operation, which allows. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.1, 10.4.x <= 10.4.3, 9.11.x <= 9.11.9 fail to properly enforce the 'Allow users to view/update archived channels' System Console setting, which allows authenticated. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.4.x <= 10.4.2, 10.5.x <= 10.5.0, 9.11.x <= 9.11.9 fail to restrict domains the LLM can request to contact upstream which allows an authenticated user to exfiltrate data from an. Rated low severity (CVSS 3.0), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost Plugin MSTeams versions <2.1.0 and Mattermost Server versions 10.5.x <=10.5.1 with the MS Teams plugin enabled fail to perform constant time comparison on a MSTeams plugin webhook secret. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.1, 10.4.x <= 10.4.3, 9.11.x <= 9.11.9 fail to check the "Allow Users to View Archived Channels" configuration when fetching channel metadata of a post from archived. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.1, 9.11.x <= 9.11.9 fail to enforce MFA checks in PUT /api/v4/users/user-id/mfa when the requesting user differs from the target user ID, which allows users with. Rated low severity (CVSS 2.2), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.1, 10.4.x <= 10.4.3, 9.11.x <= 9.11.9 fail to prevent Wrangler posts from triggering AI responses. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.1, 10.4.x <= 10.4.3, 9.11.x <= 9.11.9 fail to invalidate the cache when a user account is converted to a bot which allows an attacker to login to the bot exactly. Rated medium severity (CVSS 5.4), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.1, 9.11.x <= 9.11.9 fail to check if a file has been deleted when creating a bookmark which allows an attacker who knows the IDs of deleted files to obtain metadata. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.1, 10.4.x <= 10.4.3, 9.11.x <= 9.11.9 fail to restrict certain operations on system admins to only other system admins, which allows delegated granular. Rated medium severity (CVSS 4.7), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 9.11.x <= 9.11.8 fail to enforce proper access controls on the /api/v4/audits endpoint, allowing users with delegated granular administration roles who lack access to Compliance. Rated low severity (CVSS 2.7), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.4.x <= 10.4.2, 10.3.x <= 10.3.3, 9.11.x <= 9.11.8 fail to enforce MFA on certain search APIs, which allows authenticated attackers to bypass MFA protections via user search,. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.4.x <= 10.4.2, 10.3.x <= 10.3.3, 9.11.x <= 9.11.8 fail to fail to enforce channel conversion restrictions, which allows members with permission to convert public channels to. Rated medium severity (CVSS 5.4), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 9.11.x <= 9.11.8 fail to prompt for explicit approval before adding a team admin to a private channel, which team admins to joining private channels via crafted permalink links. Rated low severity (CVSS 3.3), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.4.x <= 10.4.2, 10.3.x <= 10.3.3, 9.11.x <= 9.11.8 fail to restrict command execution in archived channels, which allows authenticated users to run commands in archived channels. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.4.x <= 10.4.2, 10.3.x <= 10.3.3, 9.11.x <= 9.11.8, 10.5.x <= 10.5.0 fail to enforce MFA on plugin endpoints, which allows authenticated attackers to bypass MFA protections via. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.4.x <= 10.4.2, 10.3.x <= 10.3.3, 9.11.x <= 9.11.8, 10.5.x <= 10.5.0 fail to restrict bookmark creation and updates in archived channels, which allows authenticated users. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 9.11.x <= 9.11.8 fail to properly perform authorization of the Viewer role which allows an attacker with the Viewer role configured with No Access to Reporting to still view team. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.4.x <= 10.4.1, 9.11.x <= 9.11.7, 10.3.x <= 10.3.2, 10.2.x <= 10.2.2 fail to properly validate board blocks when importing boards which allows an attacker could read any. Rated critical severity (CVSS 9.9), this vulnerability is remotely exploitable, low attack complexity. Epss exploitation probability 29.3% and no vendor patch available.
Mattermost versions 10.1.x <= 10.1.3, 10.4.x <= 10.4.1, 9.11.x <= 9.11.7, 10.3.x <= 10.3.2, 10.2.x <= 10.2.2 fail to restrict channel export of archived channels when the "Allow users to view. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.4.x <= 10.4.1, 9.11.x <= 9.11.7, 10.3.x <= 10.3.2, 10.2.x <= 10.2.2 fail to use prepared statements in the SQL query of boards reordering which allows an attacker to retrieve. Rated critical severity (CVSS 9.6), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Incorrect authorization in Mattermost Boards allows an authenticated board editor to relink any editable board to an arbitrary channel by exploiting a missing PermissionManageBoardRoles check on the channelId field of the batch endpoint. Affected are Mattermost versions 11.7.x through 11.7.6, 10.11.x through 10.11.21, and 11.8.x through 11.8.3 (advisory MMSA-2026-00686). No public exploit code or CISA KEV listing has been identified at time of analysis, but the low attack complexity and network accessibility make this straightforward to execute for any authenticated board editor.
Incorrect authorization in Mattermost's Boards component across versions 11.7.x through 11.7.6, 10.11.x through 10.11.21, and 11.8.x through 11.8.3 enables privilege escalation within board management. Board editors and non-guest team members can supply arbitrary values in BoardMember.Scheme* fields through the boards member API or archive-import endpoint, effectively granting board admin rights to any user without server-side enforcement. No public exploit has been identified at time of analysis, and the vulnerability is not listed in the CISA KEV catalog.
Denial of service in Mattermost's Boards (focalboard) plugin allows any authenticated user to crash the plugin process and disrupt Boards availability for all users on the instance by sending a single malformed WebSocket message. The root cause is absent input validation on the teamId field type in custom_focalboard_SUBSCRIBE_TEAM WebSocket commands, classified under CWE-704 (Incorrect Type Conversion). Affected versions span 11.7.x through 11.7.6, 10.11.x through 10.11.21, and 11.8.x through 11.8.3; no public exploit has been identified at time of analysis.
Privilege escalation in Mattermost's channel administration API allows authenticated channel administrators to assign non-channel-scoped roles to channel members, exceeding their intended authorization boundary. Three active release lines are affected: 10.11.x through 10.11.21, 11.7.x through 11.7.6, and 11.8.x through 11.8.2. No public exploit code has been identified at time of analysis, and the vulnerability is not listed in the CISA KEV catalog.
Private channel membership disclosure in Mattermost's Boards feature allows any authenticated team member to enumerate who belongs to private channels they are not authorized to view. Affected across three concurrently maintained release trains - 11.7.x through 11.7.6, 10.11.x through 10.11.21, and 11.8.x through 11.8.3 - the flaw is exploitable by any valid team account via standard board management API calls. No public exploit or active exploitation has been identified at time of analysis; the CVSS score of 4.3 (PR:L, C:L) accurately reflects the limited but real confidentiality impact, particularly meaningful in regulated environments where private channel membership itself is sensitive.
Mattermost's Playbooks feature in versions 11.7.x through 11.7.6 and 10.11.x through 10.11.21 omits run-state enforcement on API write operations, allowing any authenticated run participant to alter completed playbook runs via REST and GraphQL endpoints. An attacker with low privileges can overwrite status, checklists, retrospective content, ownership, and participant lists on runs that should be immutable once finished, undermining post-incident audit integrity. No public exploit has been identified at time of analysis, and the vulnerability is not listed in the CISA KEV catalog.
Incorrect authorization in Mattermost's OAuth and personal access token management endpoints allows an OAuth application holding a delegated user token to call account-management endpoints beyond its intended scope, revoking the victim user's authorizations or tokens for unrelated integrations. Affected are Mattermost 11.7.0 through 11.7.6 and 10.11.0 through 10.11.21. No public exploit code has been identified and this vulnerability is not listed in the CISA KEV catalog, though the low-complexity, network-accessible nature of the flaw makes it straightforward to abuse for any actor who has legitimately obtained an OAuth delegated token.
Privilege escalation in Mattermost's Boards feature allows a low-privileged board member to elevate a guest user to Board Admin by importing a specially crafted .boardarchive file. Affected are Mattermost versions 10.11.0 through 10.11.21 and 11.7.0 through 11.7.6. No public exploit or KEV listing has been identified, but the low attack complexity and the insider-threat profile make this a meaningful risk in multi-tenant or externally-collaborative Mattermost deployments.
Incorrect authorization in Mattermost's ABAC policy unassign API endpoint allows an authenticated team administrator to remove attribute-based access control policy assignments from channels that no longer belong to their team. Affected releases are Mattermost 11.7.0 through 11.7.6 and 11.8.0 through 11.8.3, tracked as MMSA-2026-00718 (ENISA EUVD-2026-60212). The exploit window opens when a channel is migrated between teams and the endpoint fails to re-verify team membership before executing the unassignment, letting a malicious admin modify access-control policy state beyond their administrative boundary.
Privilege retention in Mattermost Boards allows a user demoted to System Guest to continue exercising Board Admin privileges via the Boards REST API or UI. Affected are Mattermost versions 11.7.0-11.7.6, 10.11.0-10.11.21, and 11.8.0-11.8.3, where the SchemeAdmin flag is not reconciled against the user's current role during or after demotion. An authenticated attacker in this state can invoke admin-only Boards operations - including modifying board permissions and settings - without detection by role-based access checks. No public exploit code is identified and no CISA KEV listing is present at time of analysis.
Server-side request forgery in the Mattermost Agents plugin MCP server (stdio mode) allows a low-privileged local attacker to make the server fetch arbitrary internal URLs submitted as file attachment references in post creation requests, enabling exfiltration of data from RFC 1918-addressed services on the internal network. Affected are Mattermost deployments running versions 10.11.x ≤ 10.11.18, 11.5.x ≤ 11.5.6, and 11.6.x ≤ 11.6.3 with the Agents plugin's MCP server active in stdio mode. No public exploit code or CISA KEV listing is present in the available data; exploitation is constrained to attackers who already have local access to the stdio MCP interface.
Markdown image rendering restrictions in Mattermost are bypassed specifically for AI bot tool result posts, enabling authenticated attackers to exfiltrate data to attacker-controlled infrastructure. Affected are Mattermost versions 10.11.x through 10.11.18, 11.5.x through 11.5.6, and 11.6.x through 11.6.3. When a victim's client renders an AI bot tool result post containing injected markdown image syntax, the client issues an outbound request to the attacker's server, leaking request metadata such as session tokens or channel context. No public exploit code exists and this vulnerability is not listed in the CISA KEV catalog at time of analysis.
Mattermost Server versions 11.3.0, 11.2.x through 11.2.2, and 10.11.x through 10.11.10 contain a server-side request forgery (SSRF) vulnerability due to improper validation of IPv4-mapped IPv6 addresses, allowing authenticated attackers to bypass reserved IP restrictions and access internal services. An attacker with login credentials can craft requests using IPv6 notation (such as [::ffff:127.0.0.1]) to reach localhost or other restricted internal endpoints that would normally be blocked. No patch is currently available for this vulnerability.
A remote code execution vulnerability (CVSS 4.3) that allows guest users without read permissions. Remediation should follow standard vulnerability management procedures.
CVE-2026-22545 is a security vulnerability (CVSS 3.1) that allows an authenticated attacker. Remediation should follow standard vulnerability management procedures.
CVE-2026-21386 is a security vulnerability (CVSS 4.3) that allows an authenticated team member. Remediation should follow standard vulnerability management procedures.
Mattermost versions 10.11.x <= 10.11.9 fail to enforce invite permissions when updating team settings, which allows team administrators without proper permissions to bypass restrictions and add users to their team via API requests. Mattermost Advisory ID: MMSA-2025-00561 [CVSS 3.8 LOW]
Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 fail to properly validate team membership when processing channel mentions which allows authenticated users to determine the existence of teams and their URL names via posting channel shortlinks and observing the channel_mentions property in the API response. [CVSS 4.3 MEDIUM]
Mattermost versions 11.1.x <= 11.1.2, 10.11.x <= 10.11.9, 11.2.x <= 11.2.1 fail to sanitize sensitive data in WebSocket messages which allows authenticated users to exfiltrate password hashes and MFA secrets via profile nickname updates or email verification events. [CVSS 5.7 MEDIUM]
Mattermost Server versions 11.1.x through 11.1.2, 10.11.x through 10.11.9, and 11.2.x through 11.2.1 inadequately enforce login method restrictions, permitting authenticated users to circumvent SSO-only requirements by authenticating with a userID instead. This allows an attacker with valid credentials to gain unauthorized access to accounts restricted to single sign-on authentication. No patch is currently available for this vulnerability.
Insufficient identity validation in Mattermost Server (versions 11.1.x through 11.2.1 and earlier) and Zoom Plugin (versions up to 1.11.0) allows authenticated users to initiate Zoom meetings as arbitrary users and modify other users' posts through direct API manipulation. An attacker with valid credentials can exploit the /api/v1/askPMI endpoint to impersonate other users and alter post content without proper authorization checks. The vulnerability affects multiple Mattermost and plugin versions with no patch currently available.
Mattermost and Zoom plugin versions fail to properly authenticate users before allowing modifications to Zoom meeting restrictions, enabling any logged-in user to alter meeting settings across arbitrary channels. Affected versions include Mattermost 11.1.x through 11.1.2, 10.11.x through 10.11.9, 11.2.x through 11.2.1, and Zoom plugin versions up to 1.11.0. No patch is currently available for this privilege escalation vulnerability.
Mattermost versions 11.1.2, 10.11.9, and 11.2.1 and earlier fail to properly enforce access controls in the Jira plugin's /create-issue API endpoint, allowing authenticated users to read restricted post content and attachments from channels they cannot access by referencing post IDs. An attacker with Jira plugin access can exploit this to enumerate and exfiltrate sensitive information from private or restricted channels. No patch is currently available for affected versions.
Mattermost versions 10.11.x <= 10.11.9 fail to properly validate channel membership at the time of data retrieval which allows a deactivated user to learn team names they should not have access to via a race condition in the /common_teams API endpoint.. Mattermost Advisory ID: MMSA-2025-00549 [CVSS 3.1 LOW]
Mattermost versions 10.11.x <= 10.11.8, 11.1.x <= 11.1.1, 11.0.x <= 11.0.6 fail to prevent infinite re-renders on API errors which allows authenticated users to cause application-level DoS via triggering unbounded component re-render loops. [CVSS 6.8 MEDIUM]
Mattermost versions 10.11.x <= 10.11.8 fail to validate input size before processing hashtags which allows an authenticated attacker to exhaust CPU resources via a single HTTP request containing a post with thousands space-separated tokens [CVSS 3.1 LOW]
Mattermost versions 11.0.x <= 11.0.2, 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12 fail to validate user permissions when deleting comments in Boards, which allows an authenticated user with the editor role to delete comments created by other users.
Mattermost versions 11.0.x <= 11.0.2, 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12 fail to to verify that the token used during the code exchange originates from the same authentication. Rated critical severity (CVSS 9.9), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 11.0.x <= 11.0.2, 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12 fail to sanitize team email addresses to be visible only to Team Admins, which allows any authenticated. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12, 11.0.x <= 11.0.3 fail to properly validate OAuth state tokens during OpenID Connect authentication which allows an. Rated critical severity (CVSS 9.9), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.11.x <= 10.11.3, 10.5.x <= 10.5.11 fail to enforce access permissions on the Agents plugin which allows other users to determine when users had read channels via channel member. Rated low severity (CVSS 3.0), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.11.x <= 10.11.3, 10.5.x <= 10.5.11, 10.12.x <= 10.12.0 fail to sanitize user data which allows system administrators to access password hashes and MFA secrets via the POST. Rated medium severity (CVSS 4.9), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.11.x <= 10.11.3, 10.5.x <= 10.5.11, 10.12.x <= 10.12.0 fail to validate the relationship between the post being updated and the MSTeams plugin OAuth flow which allows an. Rated medium severity (CVSS 5.4), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions <11 fail to enforce multi-factor authentication on WebSocket connections which allows unauthenticated users to access sensitive information via WebSocket events. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions <11.0 fail to properly enforce the "Allow users to view archived channels" setting which allows regular users to access archived channel content and files via the "Open in. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions <11 fail to properly restrict access to archived channel search API which allows guest users to discover archived public channels via the. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.11.x <= 10.11.3, 10.5.x <= 10.5.11 fail to properly validate team membership permissions in the Add Channel Member API which allows users from one team to access user metadata. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.8, 9.11.x <= 9.11.17 fail to properly validate access controls which allows any authenticated user to download sensitive files via board file download endpoint. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.10.x <= 10.10.1, 10.9.x <= 10.9.3 fail to validate import directory path configuration which allows admin users to. Rated high severity (CVSS 8.0), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.9 fail to properly validate redirect URLs which allows attackers to redirect users to malicious sites via crafted OAuth login URLs. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
Mattermost versions 10.10.x <= 10.10.1, 10.5.x <= 10.5.9, 10.9.x <= 10.9.4 fail to validate the redirect_to parameter, allowing an attacker to craft a malicious link that, once a user authenticates. Rated high severity (CVSS 7.6), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.10.x <= 10.10.1, 10.9.x <= 10.9.3 fail to properly validate cache keys for link metadata which allows authenticated users. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.10.x <= 10.10.1 fail to properly sanitize user data during shared channel membership synchronization, which allows malicious or compromised remote clusters to access sensitive. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.10.x <= 10.10.0, 10.9.x <= 10.9.3 fail to validate import data which allows a system admin to crash the server via the. Rated medium severity (CVSS 4.9), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 10.10.x <= 10.10.0, 10.9.x <= 10.9.3 fail to sanitize file names which allows users with file upload permission to overwrite file attachment. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.9.x <= 10.9.2 fails to sanitize path traversal sequences in template file destination paths, which allows a system admin. Rated medium severity (CVSS 6.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.8, 9.11.x <= 9.11.17 fail to properly validate authorization for team scheme role modifications which allows Team Admins to demote Team Members to Guests via the. Rated low severity (CVSS 3.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.8 fail to validate access controls at time of access which allows user to read a thread via AI posts. Rated low severity (CVSS 3.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.9.x <= 10.9.2, 10.10.x <= 10.10.0 fail to validate upload types in remote cluster upload sessions which allows a system. Rated medium severity (CVSS 6.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.9.x <= 10.9.2 fail to sanitize the team invite ID in the POST /api/v4/teams/:teamId/restore endpoint which allows an team. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost Server versions 10.5.x <= 10.5.9 utilizing the Agents plugin fail to reject empty request bodies which allows users to trick users into clicking malicious links via post actions. Rated low severity (CVSS 3.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.9.x <= 10.9.1, 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17 fail to properly validate file paths during plugin import operations which allows restricted admin users to. Rated medium severity (CVSS 6.8), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.5, 9.11.x <= 9.11.15, 10.8.x <= 10.8.0, 10.7.x <= 10.7.2, 10.6.x <= 10.6.5 fail to properly validate channel membership when retrieving playbook run metadata, allowing authenticated users who are playbook members but not channel members to access sensitive information about linked private channels including channel name, display name, and participant count through the run metadata API endpoint.
Mattermost versions 10.5.x <= 10.5.5, 9.11.x <= 9.11.15, 10.8.x <= 10.8.0, 10.7.x <= 10.7.2, 10.6.x <= 10.6.5 fail to properly enforce channel member management permissions when adding participants to playbook runs. This allows authenticated users with member-level permissions to bypass system admin restrictions and add or remove users to/from private channels via the playbook run participants feature, even when the 'Manage Members' permission has been explicitly removed. This can lead to unauthorized access to sensitive channel content and allow guest users to gain channel management privileges.
Mattermost versions 10.5.x <= 10.5.5, 9.11.x <= 9.11.15, 10.8.x <= 10.8.0, 10.7.x <= 10.7.2, 10.6.x <= 10.6.5 fail to properly retrieve requestorInfo from playbooks handler for guest users which allows an attacker access to the playbook run.
Mattermost versions 10.5.x <= 10.5.5, 9.11.x <= 9.11.15, 10.8.x <= 10.8.0, 10.7.x <= 10.7.2, 10.6.x <= 10.6.5 fail to properly enforce channel member management permissions in playbook runs, allowing authenticated users without the 'Manage Channel Members' permission to add or remove users from public and private channels by manipulating playbook run participants when the run is linked to a channel.
A remote code execution vulnerability (CVSS 9.9) that allows authenticated users. Critical severity with potential for significant impact on affected systems.
Mattermost versions 10.7.x <= 10.7.1, 10.6.x <= 10.6.3, 10.5.x <= 10.5.4, 9.11.x <= 9.11.13 fail to properly validate LDAP group ID attributes, allowing an authenticated administrator with PermissionSysconsoleWriteUserManagementGroups permission to execute LDAP search filter injection via the PUT /api/v4/ldap/groups/{remote_id}/link API when objectGUID is configured as the Group ID Attribute.
Mattermost versions 10.7.x <= 10.7.0, 10.5.x <= 10.5.3, 9.11.x <= 9.11.12 fails to properly enforce access control restrictions for System Manager roles, allowing authenticated users with System. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.7.x <= 10.7.0, 10.6.x <= 10.6.2, 10.5.x <= 10.5.3, 9.11.x <= 9.11.12 fails to properly invalidate personal access tokens upon user deactivation, allowing deactivated users to. Rated medium severity (CVSS 5.4), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.7.x <= 10.7.0, 10.6.x <= 10.6.2, 10.5.x <= 10.5.3, 9.11.x <= 9.11.12 fail to clear Google OAuth credentials when converting user accounts to bot accounts, allowing attackers to. Rated medium severity (CVSS 4.2), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.7.x <= 10.7.0, 10.5.x <= 10.5.3, 9.11.x <= 9.11.12 fail to properly enforce access controls for guest users accessing channel member information, allowing authenticated guest. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.7.x <= 10.7.0, 10.6.x <= 10.6.2, 10.5.x <= 10.5.3, 9.11.x <= 9.11.12 fail to properly validate permissions when changing team privacy settings, allowing team administrators. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.3, 9.11.x <= 9.11.11 fail to check `RestrictSystemAdmin` setting if user doesn't have access to `ExperimentalSettings` which allows a System Manager to access. Rated low severity (CVSS 2.7), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.2, 9.11.x <= 9.11.11 failed to properly verify a user's permissions when accessing groups, which allows an attacker to view group information via an API request. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.6.x <= 10.6.1, 10.5.x <= 10.5.2, 10.4.x <= 10.4.4, 9.11.x <= 9.11.11 fail to check the correct permissions which allows authenticated users who only have permission to invite. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.6.x <= 10.6.1, 10.5.x <= 10.5.2, 10.4.x <= 10.4.4, 9.11.x <= 9.11.11 fail to lockout LDAP users following repeated login failures, which allows attackers to lock external LDAP. Rated medium severity (CVSS 5.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Mattermost versions 10.4.x <= 10.4.2, 10.5.x <= 10.5.0, 9.11.x <= 9.11.10 fail to properly validate permissions for the API endpoint /plugins/playbooks/api/v0/signal/keywords/ignore-thread, allowing. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.4.x <= 10.4.2, 10.5.x <= 10.5.0, 9.11.x <= 9.11.10 fail to properly validate the props used by the RetrospectivePost custom post type in the Playbooks plugin, which allows an. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.4.x <= 10.4.2, 10.5.x <= 10.5.0, 9.11.x <= 9.11.10 fail to validate the uniqueness and quantity of task actions within the UpdateRunTaskActions GraphQL operation, which allows. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.1, 10.4.x <= 10.4.3, 9.11.x <= 9.11.9 fail to properly enforce the 'Allow users to view/update archived channels' System Console setting, which allows authenticated. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.4.x <= 10.4.2, 10.5.x <= 10.5.0, 9.11.x <= 9.11.9 fail to restrict domains the LLM can request to contact upstream which allows an authenticated user to exfiltrate data from an. Rated low severity (CVSS 3.0), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost Plugin MSTeams versions <2.1.0 and Mattermost Server versions 10.5.x <=10.5.1 with the MS Teams plugin enabled fail to perform constant time comparison on a MSTeams plugin webhook secret. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.1, 10.4.x <= 10.4.3, 9.11.x <= 9.11.9 fail to check the "Allow Users to View Archived Channels" configuration when fetching channel metadata of a post from archived. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.1, 9.11.x <= 9.11.9 fail to enforce MFA checks in PUT /api/v4/users/user-id/mfa when the requesting user differs from the target user ID, which allows users with. Rated low severity (CVSS 2.2), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.1, 10.4.x <= 10.4.3, 9.11.x <= 9.11.9 fail to prevent Wrangler posts from triggering AI responses. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.1, 10.4.x <= 10.4.3, 9.11.x <= 9.11.9 fail to invalidate the cache when a user account is converted to a bot which allows an attacker to login to the bot exactly. Rated medium severity (CVSS 5.4), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.1, 9.11.x <= 9.11.9 fail to check if a file has been deleted when creating a bookmark which allows an attacker who knows the IDs of deleted files to obtain metadata. Rated low severity (CVSS 3.1), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.5.x <= 10.5.1, 10.4.x <= 10.4.3, 9.11.x <= 9.11.9 fail to restrict certain operations on system admins to only other system admins, which allows delegated granular. Rated medium severity (CVSS 4.7), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 9.11.x <= 9.11.8 fail to enforce proper access controls on the /api/v4/audits endpoint, allowing users with delegated granular administration roles who lack access to Compliance. Rated low severity (CVSS 2.7), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.4.x <= 10.4.2, 10.3.x <= 10.3.3, 9.11.x <= 9.11.8 fail to enforce MFA on certain search APIs, which allows authenticated attackers to bypass MFA protections via user search,. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.4.x <= 10.4.2, 10.3.x <= 10.3.3, 9.11.x <= 9.11.8 fail to fail to enforce channel conversion restrictions, which allows members with permission to convert public channels to. Rated medium severity (CVSS 5.4), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 9.11.x <= 9.11.8 fail to prompt for explicit approval before adding a team admin to a private channel, which team admins to joining private channels via crafted permalink links. Rated low severity (CVSS 3.3), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.4.x <= 10.4.2, 10.3.x <= 10.3.3, 9.11.x <= 9.11.8 fail to restrict command execution in archived channels, which allows authenticated users to run commands in archived channels. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.4.x <= 10.4.2, 10.3.x <= 10.3.3, 9.11.x <= 9.11.8, 10.5.x <= 10.5.0 fail to enforce MFA on plugin endpoints, which allows authenticated attackers to bypass MFA protections via. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable. No vendor patch available.
Mattermost versions 10.4.x <= 10.4.2, 10.3.x <= 10.3.3, 9.11.x <= 9.11.8, 10.5.x <= 10.5.0 fail to restrict bookmark creation and updates in archived channels, which allows authenticated users. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 9.11.x <= 9.11.8 fail to properly perform authorization of the Viewer role which allows an attacker with the Viewer role configured with No Access to Reporting to still view team. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.4.x <= 10.4.1, 9.11.x <= 9.11.7, 10.3.x <= 10.3.2, 10.2.x <= 10.2.2 fail to properly validate board blocks when importing boards which allows an attacker could read any. Rated critical severity (CVSS 9.9), this vulnerability is remotely exploitable, low attack complexity. Epss exploitation probability 29.3% and no vendor patch available.
Mattermost versions 10.1.x <= 10.1.3, 10.4.x <= 10.4.1, 9.11.x <= 9.11.7, 10.3.x <= 10.3.2, 10.2.x <= 10.2.2 fail to restrict channel export of archived channels when the "Allow users to view. Rated medium severity (CVSS 4.3), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Mattermost versions 10.4.x <= 10.4.1, 9.11.x <= 9.11.7, 10.3.x <= 10.3.2, 10.2.x <= 10.2.2 fail to use prepared statements in the SQL query of boards reordering which allows an attacker to retrieve. Rated critical severity (CVSS 9.6), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.