Description
Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to verify that the channel referenced in an action cookie matches the channel of the target post, which allows an authenticated user without access to a private channel to trigger interactive post actions on posts in that channel via a cookie obtained from any accessible channel.. Mattermost Advisory ID: MMSA-2026-00690
Problem types
CWE-863: Incorrect Authorization
Product status
11.7.0 (semver)
11.6.0 (semver)
10.11.0 (semver)
11.8.0
11.7.3
11.6.5
10.11.20
Credits
minghseinyuc86595
References
mattermost.com/security-updates (MMSA-2026-00690)