CVE-2025-12689 DoS in Calls plugin via malformed UTF-8 in WebSocket request

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...