Kirki < 6.1.0 - Editor+ Arbitrary File Write via Zip Slip

Description

The plugin is vulnerable to Path Traversal (Zip Slip) via the extract_zip_file function. This makes it possible for authenticated attackers, with custom-level access and above, to write arbitrary files on the server, which can allow for remote code execution. The install_app, update_app, and get_kirki_template_from_zip code paths accept a user-supplied app src value to construct the download URL, and no sanitization is applied to prevent a crafted ZIP from being fetched and extracted with path-traversing entry names that escape the intended destination directory.