CVE-2026-9571

published 2026-07-13

CVE-2026-9571: 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…

Priority P3 38 medium 6.5 CVSS 3.1

AV N AC L PR L UI N S U C H I N A N

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

Affected

6 ranges

Vendor	Product	Version range	Fixed in
mattermost	mattermost	10.11.0 – 10.11.19	—
mattermost	mattermost	11.6.0 – 11.6.4	—
mattermost	mattermost	11.7.0 – 11.7.2	—
mattermost	mattermost_server	>= 10.11.0 < 10.11.20	10.11.20
mattermost	mattermost_server	>= 11.6.0 < 11.6.5	11.6.5
mattermost	mattermost_server	>= 11.7.0 < 11.7.3	11.7.3

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CWE-305