CVE-2026-79766: critical vulnerability in Termix-SSH Termix

Termix is a web-based server management platform with SSH terminal, tunneling, and file editing capabilities. From 2.4.1 until 2.5.1, an authenticated Termix administrator can store attacker-controlled domain and email values through PATCH /users/acme-ssl-settings and trigger their interpolation into a certbot shell command through POST /users/acme-ssl-request. In src/backend/database/routes/acme-ssl-routes.ts, child_process.execSync invokes /bin/sh -c with those values only wrapped in double quotes, so shell metacharacters can execute arbitrary operating-system commands as the Termix backend process. Both HTTP webroot and DNS Cloudflare challenge modes are affected, and compromise exposes Termix databases, process secrets, stored credentials, and network reachability. This issue is fixed in version 2.5.1.