TinyPNG < 3.6.14 - Author+ Arbitrary File Deletion via convert.path in tiny_compress_images Post Meta

Description

The plugin is vulnerable to arbitrary file deletion due to insufficient file path validation in the `delete_converted_image_size` function. 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.