Vulnerability DatabaseCVE-2026-5308
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CVE-2026-5308
Published:May 22, 2026
Updated:June 11, 2026
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
Affected Packages
https://github.com/mattermost/mattermost.git (GITHUB):
Affected version(s) >=v10.11.0 <v10.11.15
Fix Suggestion:
Update to version v10.11.15
https://github.com/mattermost/mattermost.git (GITHUB):
Affected version(s) =v11.6.0 <v11.6.1
Fix Suggestion:
Update to version v11.6.1
https://github.com/mattermost/mattermost.git (GITHUB):
Affected version(s) >=v11.4.0 <v11.4.5
Fix Suggestion:
Update to version v11.4.5
https://github.com/mattermost/mattermost.git (GITHUB):
Affected version(s) >=v11.5.0 <v11.5.4
Fix Suggestion:
Update to version v11.5.4
github.com/mattermost/mattermost (GO):
Affected version(s) >=v11.4.0 <v11.4.5
Fix Suggestion:
Update to version v11.4.5
github.com/mattermost/mattermost (GO):
Affected version(s) >=v11.5.0 <v11.5.4
Fix Suggestion:
Update to version v11.5.4
github.com/mattermost/mattermost (GO):
Affected version(s) >=v10.11.0 <v10.11.15
Fix Suggestion:
Update to version v10.11.15
github.com/mattermost/mattermost (GO):
Affected version(s) =v11.6.0 <v11.6.1
Fix Suggestion:
Update to version v11.6.1
Related Resources (1)
https://mattermost.com/security-updates
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CVSS v4
Base Score:
6.9
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
HIGH
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
4.9
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
Uncontrolled Resource Consumption
CWE-400
EPSS
Base Score:
0.05