---
id: CVE-2026-10542
title: >-
  Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7,
  10.11.x <= 10.11.22 fail to validate channel action ownership which allows
  channel managers to update actions in other channels via the channel action
  update endpo…
summary: >-
  Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7,
  10.11.x <= 10.11.22 fail to validate channel action ownership which allows
  channel managers to update actions in other channels via the channel action
  update endpo…
severity: medium
cvss: 5
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L'
cwe:
  - CWE-639
vendor: Mattermost
product: Mattermost
affected:
  - Mattermost >= 11.9.0 <= 11.9.0
  - Mattermost >= 11.8.0 <= 11.8.4
  - Mattermost >= 11.7.0 <= 11.7.7
  - Mattermost >= 10.11.0 <= 10.11.22
published: '2026-09-14'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T19:30:49.967'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-10542'
references:
  - url: 'https://mattermost.com/security-updates'
    label: responsibledisclosure@mattermost.com
tags:
  - nvd
  - cve.org
epss: 0.00129
epssPercentile: 0.02092
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-14T11:02:43.768854Z'
ingestedAt: '2026-09-14T15:23:07.462Z'
---

## Overview

Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to validate channel action ownership which allows channel managers to update actions in other channels via the channel action update endpoint.. Mattermost Advisory ID: MMSA-2026-00692

## Remediation

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