Summary Check Point Research (CPR) identified a security vulnerability in January 2025 affecting the new Rust-based kernel component of the Graphics Device Interface (commonly known as GDI) in Windows. We promptly reported this issue to Microsoft and they fixed the vulnerability starting with OS Build 26100.4202 in the KB5058499 update preview released on May 28th 2025. In the following sections, we detail the methodology of our fuzzing campaign, which targeted the Windows graphics component via...