Deactivated user accounts can continue to obtain valid OAuth access tokens via refresh token grant in Mattermost
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.9epss 0.2%
exploitation probability
0.2%top 93% of all CVEs
observed exploitation
nono source reports it
Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to invalidate OAuth refresh tokens upon user account deactivation, which allows a deactivated user or an attacker in possession of a valid refresh token to obtain new functional access tokens via the OAuth refresh token grant endpoint.. Mattermost Advisory ID: MMSA-2026-00680
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N
Affected products
Mattermost · MattermostReferences
https://mattermost.com/security-updates