CVE-2026-9571
Deactivated user accounts can continue to obtain valid OAuth access tokens via refresh token grant in Mattermost
CVSS Score
5.9
EPSS Score
0.0%
EPSS Percentile
0th
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
| CWE | CWE-305 |
| Vendor | mattermost |
| Product | mattermost |
| Published | Jul 13, 2026 |
| Last Updated | Jul 15, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
High
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
Affected Versions
Mattermost / Mattermost
11.7.0 ≤ 11.7.2 11.6.0 ≤ 11.6.4 10.11.0 ≤ 10.11.19
Credits
kirs112