# CVE-2026-9571

## Summary

- **CVE ID:** CVE-2026-9571
- **Severity:** MEDIUM
- **CVSS Score:** 5.9 (CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N)
- **CWE:** CWE-305
- **Published:** Jul 13, 2026
- **Last Modified:** Jul 15, 2026

## 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

## Affected Products

- Mattermost — Mattermost (11.7.0)
- Mattermost — Mattermost (11.6.0)
- Mattermost — Mattermost (10.11.0)
- Mattermost — Mattermost (11.8.0)
- Mattermost — Mattermost (11.7.3)
- Mattermost — Mattermost (11.6.5)
- Mattermost — Mattermost (10.11.20)

## References

- [CNA](https://mattermost.com/security-updates)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.30%
- **EPSS Percentile:** 22.8

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._