Deserialization of untrusted data in qlstudio Export User Data

Summary

The Export User Data plugin for WordPress is vulnerable to arbitrary file deletion due to insufficient file path validation in the unserialize function in all versions up to, and including, 2.2.6. This makes it possible for authenticated attackers, with subscriber-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). Successful exploitation requires an administrator to trigger a user data export while a subscriber-level (or higher) user has stored a crafted serialized XLSXWriter object payload as their display name.