CVE-2026-61898 accountsservice: shell injection via attacker-controlled ~/.pam_environment in Ubuntu language helper scripts

The Ubuntu-specific language helper scripts save-to-pam-env, update-langlist shipped with accountsservice before 23.13.9-8ubuntu7 treat the user-controlled LANGUAGE entry in /.pamenvironment as trusted input. The value is interpolated unescaped into a GNU sed replacement expression, allowing an...