CVE-2026-23532

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.21.0, a client-side heap buffer overflow occurs in the  FreeRDP clients `gdi_SurfaceToSurface` path due to a mismatch between destination rectangle clamping and the actual copy size. A malicious server can trigger a clientside heap buffer overflow, causing a crash (DoS) and potential heap corruption with codeexecution risk depending on allocator behavior and surrounding heap layout. Version 3.21.0 contains a patch for the issue.