Mattermost versions 11.7.x <= 11.7.0, 10.11.x <= 10.11.17 fail to validate bot targets when demoting users to guests which allows a lower-privileged administrator to degrade arbitrary bot accounts via the standard demote-user API.. Mattermost Advisory ID: MMSA-2026-00669
Exploitability
AV:NAC:LPR:HUI:NScope
S:UImpact
C:NI:LA:L3.8/CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:LAccess Control