Mattermost versions 9.5.x <= 9.5.3, 9.6.x <= 9.6.1 and 8.1.x <= 8.1.12 fail to perform proper authorization checks which allows a member running a playbook in an existing channel to be promoted to a channel admin
https://mattermost.com/security-updates
Source: Mitre, NVD
Published: 2024-05-26
Updated: 2025-09-30
Base Score: 6.5
Vector: CVSS2#AV:N/AC:L/Au:S/C:P/I:P/A:P
Severity: Medium
Base Score: 6.3
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
EPSS: 0.0013