CVE-2026-3637
MEDIUM4.3EPSS 0.03%Mattermost doesn't check the create_post channel permission during post edit operations
Published: 5/18/2026Modified: 6/1/2026
Description
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 packages (2)
- Go/github.com/mattermost/mattermost-serverfrom 0, < 5.3.2-0.20260316171743-090408f09f53
- Go/github.com/mattermost/mattermost/server/v8>= 10.11.0, < 10.11.14
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM4.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N |