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Status published
Medium
CVE-2025-12689
DoS in Calls plugin via malformed UTF-8 in WebSocket request
Vulnerability Description
Mattermost versions 11.0.x <= 11.0.4, 10.12.x <= 10.12.2, 10.11.x <= 10.11.6 fail to check WebSocket request field for proper UTF-8 format, which allows attacker to crash Calls plug-in via sending malformed request.
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:
- National Security Agency
References
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Affected Vendor
Mattermost
View all reports →Affected Software
Mattermost
Vulnerable Versions:
11.0.0, 10.12.0, 10.11.0, 11.1.0, 11.0.5, 10.12.3, 10.11.7
Timeline
Official Publish:
December 17th, 2025
Last Modified:
December 17th, 2025
Added to House:
July 22nd, 2026
CVSS Vectors
V3:
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weaknesses (CWE)
MITRE ATT&CK TTPs
No associated TTPs found for this vulnerability.