CVE-2026-9571

MEDIUM

Mattermost 10.11/11.6/11.7 - OAuth Refresh Token Invalidation Bypass

Title source: manual
STIX 2.1

Description

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

References (1)

Core 1
Core References
Vendor Advisory vendor-advisory
MMSA-2026-00680
https://mattermost.com/security-updates

Scores

CVSS v3 5.9
EPSS 0.0019
EPSS Percentile 8.6%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N

Details

CWE
CWE-305
Status published
Products (8)
Mattermost/Mattermost 10.11.0 - 10.11.19
Mattermost/Mattermost 10.11.20
Mattermost/Mattermost 11.6.0 - 11.6.4
Mattermost/Mattermost 11.6.5
Mattermost/Mattermost 11.7.0 - 11.7.2
Mattermost/Mattermost 11.7.3
Mattermost/Mattermost 11.8.0
mattermost/mattermost_server 10.11.0 - 10.11.20
Published Jul 13, 2026
Tracked Since Jul 13, 2026