Mattermost thread memberships persist after team removal, exposing private channel thread metadata on re-invite
8Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 3.5epss 0.2%
exploitation probability
0.2%top 95% of all CVEs
observed exploitation
nono source reports it
Mattermost versions 10.11.x <= 10.11.20, 11.7.x <= 11.7.5 Mattermost fails to remove thread membership records when a user is removed from or leaves a team, which allows a previously removed user who is later re-invited to the team to view private channel thread root post content and metadata via the team threads API.. Mattermost Advisory ID: MMSA-2026-00682
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N
Affected products
Mattermost · MattermostReferences
https://mattermost.com/security-updates