CVE-2026-3637 Details
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
A vulnerability exists in Mattermost versions 11.5.x through 11.5.1, 10.11.x through 10.11.13, and 11.4.x through 11.4.3. These versions fail to properly verify channel permissions for post creation during editing operations. This oversight allows authenticated users with revoked posting rights to alter their existing posts by sending direct API requests to the post update and patch endpoints.
Users can upgrade to Mattermost versions 11.7.0, 11.6.1, or 11.4.5 to address this vulnerability.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed May 18, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://mattermost.com/security-updates | [email protected] | Vendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-862 | Missing Authorization | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| mattermost mattermost server | >= 10.11.0, < 10.11.14 >= 11.4.0, < 11.4.4 >= 11.5.0, < 11.5.2 |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 19, 2026 | Initial Analysis | [email protected] |
| May 18, 2026 | New CVE Received | [email protected] |