The ShortPixel Adaptive Images – WebP, AVIF, CDN, Image Optimization plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the API URL Setting in all versions up to, and including, 3.10.3 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with administrator-level access, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfilteredhtml has been disabled.

The ShortPixel Adaptive Images WordPress plugin before 3.6.3 does not sanitise and escape a parameter before outputting it back in the page, leading to a Reflected Cross-Site Scripting which could be used against any high privilege users such as admin