EUVD-2026-12441
GHSA-gqv7-j2j8-qmwq
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V4 - API and Web Service URL allowlisting, SSRF prevention
MITRE ATT&CK
2 techniques across 2 tactics: Initial Access, Credential Access The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | Access to internal services, cloud metadata endpoints, or other resources not intended to be publicly accessible. Can lead to data exfiltration or further exploitation. With a CVSS score of 4.3 (MEDIUM), this represents a moderate risk. |
| Exploit ScenarioDerived | An attacker provides a URL pointing to an internal service (e.g., http://169.254.169.254/latest/meta-data/) through a vulnerable parameter, causing the server to fetch and return internal data. |
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Alert meAnalysisAIv1 – Mar 16, 2026
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.
Earlier versions of this analysis (1)
RemediationAI
Validate and whitelist allowed URLs and IP ranges. Block requests to internal/private IP ranges. Use network segmentation to limit server-side request scope.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 5 packages in go, euvd
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
Server-Side Request Forgery allows an attacker to induce the server to make HTTP requests to arbitrary destinations, including internal services. This vulnerability is classified as Server-Side Request Forgery (SSRF) (CWE-918).
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Primary rating from NVD.
CVSS VectorNVD
Lifecycle Timeline
2DescriptionCVE.org
Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to canonicalize IPv4-mapped IPv6 addresses before reserved IP validation which allows an attacker to perform SSRF attacks against internal services via IPv4-mapped IPv6 literals (e.g., [::ffff:127.0.0.1]).. Mattermost Advisory ID: MMSA-2026-00585
Executive ViewAI
CVE-2026-2455 presents moderate security risk, a server-side request forgery vulnerability rated CVSS 4.3. Users could be tricked into performing unintended actions. Organizations should apply vendor updates when available and monitor for exploitation.
Apply vendor patch. If patching is delayed: implement egress filtering, block metadata endpoints.
Threat Intelligence Overview
NVD
CVE.org
EPSS
VulDB
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Server-Side Request Forgery exploits applications that fetch remote resources based on user-supplied URLs.
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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 statemen
Same weakness CWE-918 – Server-Side Request Forgery (SSRF)
View allVendor StatusVendor
SUSE
Severity: Medium| Product | Status |
|---|---|
| openSUSE Leap 15.6 | Fixed |
| SUSE Linux Enterprise Module for Package Hub 15 SP5 | Fixed |
| SUSE Linux Enterprise Module for Package Hub 15 SP6 | Fixed |
| openSUSE Leap 15.5 | Fixed |
Exploit-DB