OS Command Injection in OPNsense os‑acme‑client Allows Root Execution via Google Cloud DNS Validation

An OS Command Injection vulnerability was discovered in the Google Cloud DNS validation module of the OPNsense os-acme-client plugin through 4.17. The DnsGcloud::prepare() method decodes the dns_gcloud_key model field and directly interpolates the string fields gcloud_account and gcloud_project into a shell command passed to proc_open() via LeUtils::run_shell_command() without any validation or escaping. A remote authenticated user with privileges to issue or renew certificates through the WebGUI/API can achieve arbitrary code execution as root.