CVE-2026-55194: Freerdp

Critical severity, CVSS 9.8. EPSS: 0.6% chance of exploitation in the next 30 days.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, rpc_client_recv_fragment in libfreerdp/core/gateway/rpc_client.c ensures the response reassembly stream capacity using only the server-declared alloc_hint rather than the actual StubLength about to be written. A malicious TS Gateway can send a PTYPE_RESPONSE with a small alloc_hint and a much larger frag_length, causing Stream_Write to copy attacker-controlled stub data beyond the 4096-byte pdu->s buffer. This can crash the client and may permit code execution through heap corruption. This issue is fixed in version 3.27.0.

Affected products

• Freerdp Freerdp: before 3.27.0 (fixed in 3.27.0)

Published 2026-08-19. Last modified 2026-09-24.