CVE-2026-10527 — Boards plugin retains Board Admin rights for users demoted to System Guest
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…
Published: 2026-08-17 · CVSS: 6.3 · CVSS 3.1
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
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7