The Powerkit plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the Lazy Load module's image processing in all versions up to, and including, 3.0.4. This is due to the 'content_process_images' function using a flawed regex-based HTML attribute parser. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.