CVE-2026-1629 Permalink Preview Information Disclosure After Permission Revocation
Users retain access to private channel content via cached permalink previews after losing channel access, requiring an upgrade to fix.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-1629?
CVE-2026-1629 is a medium-severity vulnerability in Mattermost Mattermost Server, published on 16 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Mattermost versions 10.11.x <= 10.11.10 Fail to invalidate cached permalink preview data when a user loses channel access which allows the user to continue viewing private channel content via previously cached permalink previews until cache reset or relogin.. Mattermost Advisory ID: MMSA-2026-00580
Weakness: CWE-672
Which versions are affected by CVE-2026-1629?
It affects 1 product.
Products include Mattermost Mattermost Server.
How do I fix CVE-2026-1629?
No fix has been published for CVE-2026-1629 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-1629 being exploited?
There is no known exploitation of CVE-2026-1629 in the wild and no public exploit code.
Other vulnerabilities in Mattermost Mattermost Server
- CVE-2025-12419 Account takeover on OAuth/OpenID-enabled servers
- CVE-2025-12421 Account Takeover via Code Exchange Endpoint
- CVE-2025-4981 Path Traversal Leading to RCE by Any Authenticated Mattermost User
- CVE-2025-20051 Arbitrary file read via block duplication in Mattermost Boards
- CVE-2025-25279 Arbitrary file read in Mattermost Boards via import & export board archive
Sources
Also known as GHSA-f77j-wjfq-qgmp.