Swiss Toolkit For WP <= 1.4.6 - Authenticated (Author+) Arbitrary File Upload via upload_extension_files()

Summary

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.

Timeline

1. Jul 11, 2026, 3:44 AM UTCCVE published
2. Jul 13, 2026, 2:35 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: total

3. Jul 13, 2026, 2:39 PM UTCRecord last updated

Affected versions

• wpmessiah Swiss Toolkit For WP

  through 1.4.6

References 5