CVE-2026-23534: Freerdp

Critical severity, CVSS 9.8. EPSS: 0.5% chance of exploitation in the next 30 days.

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 ClearCodec bands decode path when crafted band coordinates allow writes past the end of the destination surface buffer. A malicious server can trigger a client‑side heap buffer overflow, causing a crash (DoS) and potential heap corruption with code‑execution risk depending on allocator behavior and surrounding heap layout. Version 3.21.0 contains a patch for the issue.

Affected products

• Freerdp Freerdp: before 3.21.0 (fixed in 3.21.0)

Published 2026-01-19. Last modified 2026-07-15.