The Swiss Toolkit For WP plugin for WordPress is vulnerable to arbitrary file upload due to a...

The Swiss Toolkit For WP plugin for WordPress is vulnerable to arbitrary file upload due to a flawed file type validation bypass in the upload_extension_files() function in all versions up to, and including, 1.4.6. The upload_extension_files() function hooks into WordPress's wp_check_filetype_and_ext filter and uses strpos() to check if a filename contains a configured extension string, rather than verifying the actual file extension. This makes it possible for authenticated attackers, with Author-level access and above, to upload arbitrary files (including PHP) on the affected site's server which may make remote code execution possible, granted the "Enhanced Multi-Format Image Support" feature is enabled with at least one extension (e.g., avif) in the allowed formats.