CVE-2026-26246
March 16, 2026
Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to bound memory allocation when processing PSD image files which allows an authenticated attacker to cause server memory exhaustion and denial of service via uploading a specially crafted PSD file. Mattermost Advisory ID: MMSA-2026-00572
Affected Packages
github.com/mattermost/mattermost (GO):
Affected version(s) =v11.3.0 <v11.3.1Fix Suggestion:
Update to version v11.3.1github.com/mattermost/mattermost-server (GO):
Affected version(s) >=v11.3.0-rc1 <v11.3.1Fix Suggestion:
Update to version v11.3.1github.com/mattermost/mattermost (GO):
Affected version(s) >=v11.2.0 <v11.2.3Fix Suggestion:
Update to version v11.2.3github.com/mattermost/mattermost (GO):
Affected version(s) >=v10.11.0 <v10.11.11Fix Suggestion:
Update to version v10.11.11github.com/mattermost/mattermost/server/v8 (GO):
Affected version(s) >=v8.0.0-20230429093631-aac4f2337933 <v8.0.0-20260115183946-38b413a27604Fix Suggestion:
Update to version v8.0.0-20260115183946-38b413a27604github.com/mattermost/mattermost-server (GO):
Affected version(s) >=v10.11.0-rc1 <v10.11.11Fix Suggestion:
Update to version v10.11.11github.com/mattermost/mattermost-server (GO):
Affected version(s) >=v11.2.0-rc1 <v11.2.3Fix Suggestion:
Update to version v11.2.3Related Resources (4)
Do you need more information?
Contact UsCVSS v4
Base Score:
5.3
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
LOW
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
LOW
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
4.3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Weakness Type (CWE)
Memory Allocation with Excessive Size Value
EPSS
Base Score:
0.04
