Deactivated user accounts can continue to obtain valid OAuth access tokens via refresh token grant in Mattermost
Summary
| CVE | CVE-2026-9571 |
|---|---|
| State | PUBLISHED |
| Assigner | Mattermost |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-07-13 09:16:25 UTC |
| Updated | 2026-07-15 05:17:25 UTC |
| 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 |
Risk And Classification
Primary CVSS: v3.1 6.5 MEDIUM from [email protected]
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
EPSS: 0.001740000 probability, percentile 0.070480000 (date 2026-07-14)
Problem Types: CWE-305 | CWE-305 CWE-305 – Authentication Bypass by Primary Weakness
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 6.5 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N |
| 3.1 | [email protected] | Secondary | 5.9 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N |
| 3.1 | CNA | CVSS | 5.9 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
LowUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
NoneAvailability
NoneCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Application | Mattermost | Mattermost Server | All | All | All | All |
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Mattermost | Mattermost | affected 11.7.0 11.7.2 semver | Not specified |
| CNA | Mattermost | Mattermost | affected 11.6.0 11.6.4 semver | Not specified |
| CNA | Mattermost | Mattermost | affected 10.11.0 10.11.19 semver | Not specified |
| CNA | Mattermost | Mattermost | unaffected 11.8.0 | Not specified |
| CNA | Mattermost | Mattermost | unaffected 11.7.3 | Not specified |
| CNA | Mattermost | Mattermost | unaffected 11.6.5 | Not specified |
| CNA | Mattermost | Mattermost | unaffected 10.11.20 | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| mattermost.com/security-updates | [email protected] | mattermost.com | Vendor Advisory |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: kirs112 (en)
Additional Advisory Data
Solutions
CNA: Update Mattermost to versions 11.8.0, 11.7.3, 11.6.5, 10.11.20 or higher.
There are currently no legacy QID mappings associated with this CVE.