{"id":"CVE-2025-12689","title":"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.","summary":"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.","severity":"medium","cvss":6.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-1287"],"vendor":"mattermost","product":"mattermost_server","affected":["mattermost_server >= 10.11.0, < 10.11.7","mattermost_server >= 10.12.0, < 10.12.3","mattermost_server >= 11.0.0, < 11.0.5"],"patched":["mattermost_server 11.0.5"],"published":"2025-12-17","updated":"2026-10-13","sourceUpdated":"2026-10-13T11:10:00.203","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-12689","references":[{"url":"https://mattermost.com/security-updates","label":"responsibledisclosure@mattermost.com"}],"tags":["nvd"],"epss":0.00288,"epssPercentile":0.19656,"ingestedAt":"2026-10-13T11:23:51.121Z","slug":"CVE-2025-12689","body":"## Overview\n\nMattermost 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.\n\n## Affected\n\n- `mattermost_server >= 10.11.0, < 10.11.7`\n- `mattermost_server >= 10.12.0, < 10.12.3`\n- `mattermost_server >= 11.0.0, < 11.0.5`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `mattermost_server 11.0.5`","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":35.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}