Outline

API key scope bypass in Outline prior to 1.8.0 allows an authenticated attacker holding a limited-scope API key or OAuth token to perform actions on restricted endpoints by exploiting a URL fragment handling discrepancy. The `AuthenticationHelper.canAccess` function evaluates authorization against the fragment-appended URL path rather than the actual routed endpoint, enabling privilege escalation beyond the key's intended permissions. No public exploit code or active exploitation has been identified at time of analysis, but the low attack complexity (PR:L, AC:L) makes this straightforward to exploit for any valid API key holder.

Outline's Slack integration callback endpoint (GET /auth/slack.post) in versions before 1.7.1 accepts an unsigned, session-independent OAuth state parameter, enabling an attacker to hijack the account-linking flow for any logged-in Outline user. By obtaining a valid Slack OAuth authorization code for the same Outline Slack app and delivering a crafted callback URL to a victim, the attacker silently links the victim's Outline account to the attacker's Slack team_id and user_id, granting ongoing ability to query the victim's private Outline content via the Slack /outline search command. SSVC confirms a proof of concept exists; however, EPSS stands at 0.01% and CISA KEV status is absent, indicating exploitation is not yet widespread.

Broken authorization logic across two sequential sharing API calls in Outline collaborative documentation (prior to 1.7.0) allows any authenticated low-privilege user to publish arbitrary documents as publicly accessible shares, exposing content to unauthenticated users without possessing legitimate share rights over the target document. The flaw exploits a permission gap in shares.create (which skips share-permission validation when published=false) combined with a disjunctive OR policy in shares.update that can be satisfied by unrelated collection-level share permissions. No public exploit code repository has been identified in the provided references, though SSVC classifies exploitation evidence at POC level; the vulnerability is not listed in CISA KEV, and EPSS sits at 0.04% (12th percentile), indicating low current real-world exploitation.

Zip extraction sandbox escape in Outline (self-hosted collaborative knowledge base) before 1.7.0 lets an authenticated user with import privileges write an attacker-named file into the server's process working directory instead of the isolated extraction folder. A crafted import archive whose nested entry path exceeds the 4096-byte MAX_PATH_LENGTH causes the trimFileAndExt helper to collapse the path to a bare filename, and the resulting file survives normal import cleanup. Publicly available exploit code exists per SSVC (POC), but there is no public exploit identified in the wild and EPSS probability is very low (0.04%).

Broken object-level authorization in Outline (self-hosted collaborative documentation) versions 0.84.0 through 1.7.0 lets an authenticated user subscribe to any document across any team, including documents they have no read access to. The subscriptions.create API validates only the collection branch when both collectionId and documentId are submitted, but the subscriptionCreator command writes the record against the unvalidated documentId. Publicly available exploit path is described in the vendor advisory (SSVC 'poc'); EPSS is very low at 0.03% (8th percentile), indicating no observed mass exploitation.

Privilege escalation in Outline (the collaborative wiki/knowledge-base) versions 0.84.0 through 1.6.1 lets a malicious OAuth client smuggle the wildcard '*' scope by requesting a mixed scope string such as 'read *', turning a token the user believes is read-only into one with full write, delete, and admin API access. The flaw is a logic error in OAuthInterface.validateScope(), which uses Array.some() so the whole requested scope set passes validation as long as one element is valid. Publicly available exploit code exists (SSVC: PoC), but there is no evidence of active exploitation and EPSS is very low at 0.03% (8th percentile).

Stored cross-site scripting in Outline collaborative documentation (versions 0.84.0 through 1.6.1) lets an authenticated user inject a mention in the comment section whose href attribute is never validated, so dangerous protocols such as javascript: survive rendering and execute in a viewing user's browser. When a victim interacts with the malicious mention, attacker-controlled script runs in their session, enabling account-context actions and data theft; publicly available exploit code exists but there is no evidence of active exploitation and EPSS probability is negligible (0.04%). The issue is resolved in Outline 1.7.0.

Cross-workspace document disclosure in Outline (getoutline) versions 0.86.0 through 1.6.x lets an authenticated user mint a public share link for any document on the platform, then read its full contents. The flaw is an insecure direct object reference (IDOR) in the shares.create API: when a request supplies both collectionId and documentId, authorization validates only the collection and never checks that the caller may access the named document, so it works even against documents in other workspaces. A proof-of-concept is referenced by the GitHub advisory (SSVC 'poc'), but EPSS is very low (0.03%, 7th percentile) and it is not in CISA KEV, so this is publicly demonstrated but not confirmed as actively exploited.

Account takeover in Outline collaborative documentation service versions 0.86.0 through 1.5.x enables unauthenticated attackers to brute force Email OTP codes due to insufficient validation logic combined with rate limiter bypass. Attackers can submit unlimited OTP attempts within the code's validity window, compromising user accounts. CVSS 9.1 (Critical) severity reflects network-accessible attack vector requiring no privileges or user interaction. No public exploit identified at time of analysis, though the authentication bypass mechanism is documented in GHSA-cwhc-53hw-qqx6.

Outline versions before 1.5.0 allow authenticated users to enumerate sensitive metadata from documents they shouldn't access via a logic flaw in the events.list API endpoint, exposing document IDs, activity timestamps, and titles of deleted items. This information disclosure enables attackers to bypass UUID protections and craft follow-up IDOR attacks to access restricted documents. The vulnerability requires authentication but affects all users with access to the Outline instance.

An Insecure Direct Object Reference (IDOR) vulnerability in Outline's document restoration logic allows any authenticated team member to restore, view, and take ownership of deleted drafts belonging to other users, including administrators. Attackers can access sensitive private information and lock the original owners out of their own content by exploiting the missing ownership validation during the restore process. This vulnerability affects Outline versions prior to 1.4.0 and carries a high CVSS score of 8.1, though no active exploitation or proof-of-concept code has been reported.

Outline versions prior to 1.4.0 fail to validate attachment file paths during JSON import, allowing authenticated attackers with high privileges to traverse the directory structure and read arbitrary files from the server. Public exploit code exists for this path traversal vulnerability, and no patch is currently available for affected deployments.

Outline is a service that allows for collaborative documentation. [CVSS 5.3 MEDIUM]

Outline is a service that allows for collaborative documentation. Prior to 1.1.0, a privilege escalation vulnerability exists in the Outline document management system due to inconsistent authorization checks between user and group membership management endpoints. [CVSS 7.6 HIGH]

Outline versions up to - contains a vulnerability that allows attackers to potentially execute arbitrary code with elevated system privileges (CVSS 7.8).

Outline is a service that allows for collaborative documentation. Rated medium severity (CVSS 6.8), this vulnerability is remotely exploitable, low attack complexity. This Cross-Site Scripting (XSS) vulnerability could allow attackers to inject malicious scripts into web pages viewed by other users.

Outline is an open source, collaborative document editor. Rated medium severity (CVSS 5.4), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.

An issue in Outline <= v0.76.1 allows attackers to execute a session hijacking attack via user interaction with a crafted magic sign-in link. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

An issue in Outline <= v0.76.1 allows attackers to redirect a victim user to a malicious site via intercepting and changing the state cookie. Rated medium severity (CVSS 6.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Cross-site Scripting (XSS) - Stored in GitHub repository outline/outline prior to 0.70.1. Rated medium severity (CVSS 5.4), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available.

Cross-site Scripting (XSS) - Stored in GitHub repository outline/outline prior to v0.64.4. Rated medium severity (CVSS 5.4), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available.