CVE-2026-10527 — Boards plugin retains Board Admin rights for users demoted to System Guest

CVE-2026-10527

Boards plugin retains Board Admin rights for users demoted to System Guest PUBLISHED

Description (CNA)

Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21, 11.8.x <= 11.8.3 fails to reconcile SchemeAdmin flags with a user's current role which allows a user demoted to System Guest to retain Board Admin privileges and perform admin-only operations via the Boards REST API or UI.. Mattermost Advisory ID: MMSA-2026-00691

Affected (CNA)

Vendor / product	Versions
Mattermost / Mattermost	affected 11.7.0 through 11.7.6; affected 10.11.0 through 10.11.21; affected 11.8.0 through 11.8.3; unaffected 11.9.0; unaffected 11.7.7; unaffected 10.11.22; unaffected 11.8.4

CWE

CWE-863

References

https://mattermost.com/security-updates

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.