CVE-2026-3637

Mattermost fails to enforce create_post permission when editing posts

State: Published
Severity: 4.3 Medium
Published: May 18, 2026
Updated: May 18, 2026
Reserved: Mar 6, 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

Scores

CVSS	Score	Vector	Source
3.1	4.3 Medium	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N	Mattermost

Weaknesses

CWE-862 Missing Authorization

Affected Products

Product	Versions
MattermostMattermost	11.5.0 through 11.5.1Affected 10.11.0 through 10.11.13Affected 11.4.0 through 11.4.3Affected 11.6.0Not affected 11.5.2Not affected 10.11.14Not affected 11.4.4Not affected

References

MMSA-2026-00627vendor-advisory

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