CVE-2026-64620

Name of the Vulnerable Software and Affected Versions FreeRDP versions prior to 3.28.0

Description A heap-based buffer overflow exists in the crypto rsa common() function within the libfreerdp/crypto/crypto.c file. The issue occurs because the function uses BN bn2bin() to write a modular-exponentiation result into the output buffer before validating if output length exceeds out length. When the server is configured with RDP Standard Security, an unauthenticated remote attacker can send a crafted encrypted client random. Since the server publishes its RSA public key, the attacker can forge a ciphertext that decrypts to a value up to the full modulus length (e.g., 256 bytes for RSA-2048), overflowing the fixed 32-byte heap buffer by approximately 224 bytes. This can lead to a denial of service or potentially allow the execution of arbitrary code.

Recommendations Update FreeRDP to version 3.28.0.