Mattermost · Mattermost · CVE-2026-9693
**Name of the Vulnerable Software and Affected Versions**
Mattermost versions 10.11.0 through 10.11.20
Mattermost versions 11.7.0 through 11.7.5
**Description**
The software fails to remove thread membership records when a user leaves or is removed from a team. This allows a user who is subsequently re-invited to the team to access private channel thread root post content and metadata through the team threads API.
**Recommendations**
Update Mattermost versions 10.11.0 through 10.11.20 to a version newer than 10.11.20.
Update Mattermost versions 11.7.0 through 11.7.5 to a version newer than 11.7.5.