Missing per-channel team-scope check in ABAC access control policy unassign allows cross-team policy removal
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 4.2epss 0.1%
exploitation probability
0.1%top 95% of all CVEs
observed exploitation
nono source reports it
Mattermost versions 11.7.x <= 11.7.6, 11.8.x <= 11.8.3 The access control policy unassign endpoint fails to re-validate that each target channel still belongs to the requesting admin's team, which allows an authenticated team administrator to remove ABAC (attribute-based access control) policy assignments from channels outside their team via the policy unassign API after a channel has been moved to another team.. Mattermost Advisory ID: MMSA-2026-00718
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:H/A:N
Affected products
Mattermost · MattermostReferences
https://mattermost.com/security-updates