Denial of Service Vulnerability in Mattermost Product from Mattermost
CVE-2026-5308

4.9MEDIUM

Key Information:

Vendor

Mattermost
Status
Mattermost
Vendor
CVE Published:
22 May 2026

What is CVE-2026-5308?

Mattermost versions up to 11.6.0 in the 11.6.x series, 11.5.3 in the 11.5.x series, 11.4.4 in the 11.4.x series, and 10.11.14 in the 10.11.x series are susceptible to a denial of service attack. This vulnerability arises from the failure to enforce request body size limits on plugin HTTP endpoints. An attacker could exploit this weakness by sending specially crafted oversized HTTP requests, potentially disrupting service availability.

Affected Version(s)

Mattermost 11.6.0

Mattermost 11.5.0 <= 11.5.3

Mattermost 11.4.0 <= 11.4.4

References

https://mattermost.com/security-updates
vendor-advisory

CVSS V3.1

Score:
4.9
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
High
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

thecybertantrik
.