CVE-2026-5308 Details
Description
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to enforce request body size limits on plugin HTTP endpoints which allows an attacker to cause a denial of service via crafted oversized HTTP requests.. Mattermost Advisory ID: MMSA-2026-00646
A denial-of-service vulnerability has been identified in Mattermost versions 11.6.0, 11.5.3, 11.4.4, and 10.11.14. The issue arises because these versions do not properly enforce request body size limits on plugin HTTP endpoints. This oversight allows an attacker to disrupt service by sending crafted oversized HTTP requests.
Users can upgrade to Mattermost versions 11.8.0 or 11.7.0 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 22, 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-400 | Uncontrolled Resource Consumption | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| mattermost mattermost server | >= 10.11.0, < 10.11.15 >= 11.4.0, < 11.4.5 >= 11.5.0, < 11.5.4 >= 11.6.0, < 11.6.1 |
CPE
Remediation
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Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 23, 2026 | CVE Translated | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 22, 2026 | Initial Analysis | [email protected] |
| May 22, 2026 | New CVE Received | [email protected] |