CVE-2025-9076 - CVE House
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Status published Medium CVE-2025-9076

Mattermost Server exposes sensitive user credentials during shared channel membership synchronization

Vulnerability Description

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.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

The following person or organization is credited with identifying this vulnerability, as recorded in the NVD database:

  • daw10

References

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Affected Vendor

Affected Software

Mattermost
Vulnerable Versions:
10.10.0, 10.11.0, 10.10.2

Timeline

Official Publish: September 15th, 2025
Last Modified: September 15th, 2025
Added to House: July 22nd, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N

Weaknesses (CWE)

CWE-862

MITRE ATT&CK TTPs

T1190 Exploit Public-Facing Application
Initial Access
T1068 Exploitation for Privilege Escalation
Privilege Escalation
T1078 Valid Accounts
Persistence
T1531 Account Access Removal
Impact