TinyPNG <= 3.6.13 - Authenticated (Author+) Arbitrary File Deletion via 'convert.path' in 'tiny_compress_images' Post Meta

The TinyPNG – JPEG, PNG & WebP image compression plugin for WordPress is vulnerable to arbitrary file deletion due to insufficient file path validation in the delete_converted_image_size function in all versions up to, and including, 3.6.13. This makes it possible for authenticated attackers, with author-level access and above, to delete arbitrary files on the server, which can easily lead to remote code execution when the right file is deleted (such as wp-config.php). An attacker can exploit this by injecting an arbitrary server file path into the 'convert.path' field of the 'tiny_compress_images' post meta on an attachment they own, then triggering attachment deletion to invoke the vulnerable code path.