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

CVE-2026-15754

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

Description (CNA)

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

Affected (CNA)

Vendor / product	Versions
Mattermost / Mattermost	affected 11.7.0 through 11.7.6; affected 11.8.0 through 11.8.3; unaffected 11.9.0; unaffected 11.7.7; unaffected 11.8.4

CWE

CWE-863

References

https://mattermost.com/security-updates

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.