CVE-2026-15754 Missing per-channel team-scope check in ABAC access control policy unassign allows cross-team policy removal

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...

CVE-2026-15754 Missing per-channel team-scope check in ABAC access control policy unassign allows cross-team policy removal

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...

CVE-2026-15754

Mattermost 11.7.x (≤11.7.6) and 11.8.x (≤11.8.3) have a missing per-channel team-scope check in the ABAC policy unassign endpoint, allowing an authenticated team administrator to remove ABAC policy assignments from channels that have been moved to another team. Impact is integrity-focused (CVSS 4...

EUVD-2026-60212

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...

PT-2026-76668

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...