Vulnerability · Published May 11, 2026 · Assigned by GitHub_M

CVE-2026-44695Outline: Slack OAuth state can link a victim Outline account to an attacker Slack identity

Medium 5.8

In plain English

A medium-severity cross-site request forgery in outline from outline. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities).

Severity (CVSS 3.1)5.8Medium

Exploit odds (30 days)0.1%top 97.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

Outline is a service that allows for collaborative documentation. Prior to 1.7.1, the Slack integration callback for GET /auth/slack.post accepts an unsigned, session-independent OAuth state value. A third party who can obtain a Slack OAuth code for the same Outline Slack client can make a logged-in Outline user complete the callback and link that user's Outline account to the attacker's Slack team_id and user_id. The linked Slack identity can then use the Slack /outline search command as the victim Outline user. This vulnerability is fixed in 1.7.1.

Affected products (as reported)

Vendor	Product	Versions
outline	outline	< 1.7.1

Weakness: CWE-352 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:N/A:N

References

https://github.com/outline/outline/security/advisories/GHSA-mjgw-5j7q-gv8v x_refsource_CONFIRM