---
id: CVE-2026-3637
title: >-
  Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3
  fail to check the create_post channel permission during post edit operations
  which allows an authenticated attacker with revoked posting privileges to
  modify the…
summary: >-
  Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3
  fail to check the create_post channel permission during post edit operations
  which allows an authenticated attacker with revoked posting privileges to
  modify the…
severity: medium
cvss: 4.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N'
cwe:
  - CWE-862
vendor: mattermost
product: mattermost_server
affected:
  - 'mattermost_server >= 10.11.0, < 10.11.14'
  - 'mattermost_server >= 11.4.0, < 11.4.4'
  - 'mattermost_server >= 11.5.0, < 11.5.2'
patched:
  - mattermost_server 11.5.2
published: '2026-05-18'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T20:10:00.190'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-3637'
references:
  - url: 'https://mattermost.com/security-updates'
    label: responsibledisclosure@mattermost.com
tags:
  - nvd
epss: 0.00254
epssPercentile: 0.15777
ingestedAt: '2026-10-14T20:53:12.296Z'
---

## Overview

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to check the create_post channel permission during post edit operations which allows an authenticated attacker with revoked posting privileges to modify their existing posts via direct API requests to the post update and patch endpoints.. Mattermost Advisory ID: MMSA-2026-00627

## Affected

- `mattermost_server >= 10.11.0, < 10.11.14`
- `mattermost_server >= 11.4.0, < 11.4.4`
- `mattermost_server >= 11.5.0, < 11.5.2`

## Remediation

Upgrade past the affected range:

- `mattermost_server 11.5.2`