PT-2026-41642 · Mattermost · Mattermost

0X7Oda7123 · Published 2026-05-18 · Updated 2026-05-18 · CVE-2026-3637

Positive Technologies (AI Summary)

CVSS v3.1

4.3

Medium

Base vector

AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Name of the Vulnerable Software and Affected Versions Mattermost versions 11.5.0 through 11.5.1 Mattermost versions 10.11.0 through 10.11.13 Mattermost versions 11.4.0 through 11.4.3

Description An issue exists where the software fails to verify the create post channel permission during post edit operations. This allows an authenticated attacker who has had their posting privileges revoked to modify their existing posts by sending direct API requests to the post update and patch endpoints.

Recommendations Update versions 11.5.0 through 11.5.1 to a version newer than 11.5.1. Update versions 10.11.0 through 10.11.13 to a version newer than 10.11.13. Update versions 11.4.0 through 11.4.3 to a version newer than 11.4.3.

Fix

Missing Authorization

Weakness Enumeration

CWE-862

Related Identifiers

CVE-2026-3637

GHSA-V549-XX3C-6PC8

Affected Products

Mattermost

References · 7

• https://mattermost.com/security-updates · Vendor Advisory
• https://osv.dev/vulnerability/GHSA-v549-xx3c-6pc8 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-3637 · Security Note
• https://github.com/mattermost/mattermost/commit/090408f09f53ffc9afc6c65c7c7c1fd3a8cd22f3 · Note
• https://github.com/mattermost/mattermost · Note
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-3637 · Note
• https://t.me/CVEtracker/54103 · Telegram Post