CVE-2026-9571
Deactivated user accounts can continue to obtain valid OAuth access tokens via refresh token grant in Mattermost
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
No summary for this CVE yet.
CVSS Vector Breakdown
Exploitability
AV:NAttack VectorNetwork
AC:HAttack ComplexityHigh
PR:HPrivileges RequiredHigh
UI:NUser InteractionNone
Scope
S:UScopeUnchanged
Impact
C:HConfidentialityHigh
I:HIntegrityHigh
A:NAvailabilityNone
Weaknesses
Affected Products
Exploitability
Official Patch Available
References
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