CVE-2025-9076
September 15, 2025
Mattermost versions 10.10.x <= 10.10.1 fail to properly sanitize user data during shared channel membership synchronization, which allows malicious or compromised remote clusters to access sensitive user information via unsanitized user objects. This vulnerability affects Mattermost Server instances with shared channels enabled.
Affected Packages
github.com/mattermost/mattermost/server/v8 (GO):
Affected version(s) >=v8.0.0-20230429093631-aac4f2337933 <v8.0.0-20250729073403-517ae758cd02Fix Suggestion:
Update to version v8.0.0-20250729073403-517ae758cd02github.com/mattermost/mattermost-server (GO):
Affected version(s) >=v10.10.0 <v10.10.2Fix Suggestion:
Update to version v10.10.2github.com/mattermost/mattermost (GO):
Affected version(s) >=v10.10.0 <v10.10.2Fix Suggestion:
Update to version v10.10.2Related Resources (3)
Do you need more information?
Contact UsCVSS v4
Base Score:
8.5
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
HIGH
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
6.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
Weakness Type (CWE)
Missing Authorization
EPSS
Base Score:
0.05
