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

Medium 5.8 Published 11 May 2026 Updated 12 May 2026

Attackers can link victim Outline accounts to attacker Slack identities via unsigned OAuth state, enabling unauthorized access to victim data.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: None listed

What is CVE-2026-44695?

CVE-2026-44695 is a medium-severity vulnerability in outline, published on 11 May 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

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.

Weakness: CWE-352

Which versions are affected by CVE-2026-44695?

It affects 1 product.

Products include Getoutline Outline.

How do I fix CVE-2026-44695?

No fix has been published for CVE-2026-44695 yet. Limit exposure of the affected software until one is available.

Is CVE-2026-44695 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-44695 exists.

Sources

Also known as GHSA-mjgw-5j7q-gv8v.