CVE-2026-44695: Outline account linking bypass in Slack integration callback

CVE-2026-44695 · Severity: medium · CVSS 5.8 · Published 2026-05-11

Outline, a collaborative documentation platform, contains a security flaw in its Slack integration. An attacker can trick a logged-in user into clicking a malicious link that connects the user's Outline account to the attacker's Slack account. Once linked, the attacker can use Slack commands to search for and view private document titles, summaries, and links belonging to the victim.

Technologies: Jigsaw Outline. Vendors: Jigsaw.

Quick answers

Is CVE-2026-44695 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-44695 being exploited in the wild.
How severe is CVE-2026-44695?
Medium severity, with a CVSS score of 5.8, published 11 May 2026.
Which products and versions are affected?
Jigsaw Outline < 1.7.1.
Is there a fix for CVE-2026-44695?
A patch was published on 2026-05-11: Fix released in version 1.7.1 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-44695 attacked?
It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-44695?
Check whether you run Jigsaw Outline at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The Slack integration callback for 'GET /auth/slack.post' fails to properly validate the OAuth 'state' parameter, accepting unsigned and session-independent values. This lack of a nonce or cryptographic signature allows for a Cross-Site Request Forgery (CSRF) style attack where an attacker can provide their own Slack OAuth code and state to a logged-in victim. When the victim's browser processes the callback, the server creates an 'IntegrationType.LinkedAccount' row mapping the victim's Outline 'userId' to the attacker's Slack 'team_id' and 'user_id'. Consequently, the attacker can execute the '/outline' search command from their Slack workspace to retrieve search results (titles, snippets, and links) authorized for the victim user. This issue is resolved in version 1.7.1.

Affected products

  • Outline Outline < 1.7.1

Timeline

  • 2026-05-07: advisory: GitHub Security Advisory published by maintainers
  • 2026-05-11: disclosed: CVE published to NVD
  • 2026-05-11: patched: Fix released in version 1.7.1

References

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