Nginx UI: Backup restore follows crafted symlinks into the live Nginx configuration path before restore flags are applied

Nginx UI is a web user interface for the Nginx web server. From 2.0.0 until 2.5.0, internal/backup/restore.go extracts inner archives before applying the restore_nginx and restore_nginx_ui flags and permits symlinks targeting the live Nginx configuration path. An authenticated user who can create and restore backups can craft a valid backup that places a symlink in the staging tree and then writes a regular file through that link, even when both restore flags are false. This can persistently inject configuration or cause denial of service when the modified files are later consumed. This issue is fixed in version 2.5.0.