---
id: CVE-2026-9571
title: >-
  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 …
summary: >-
  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 …
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N'
cwe:
  - CWE-305
published: '2026-07-13'
updated: '2026-07-13'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-9571'
references:
  - url: 'https://mattermost.com/security-updates'
    label: responsibledisclosure@mattermost.com
tags:
  - nvd
ingestedAt: '2026-07-13T12:26:58.155Z'
epss: 0.00303
epssPercentile: 0.23197
---

## Overview

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

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.