CVE-2026-42859

Name of the Vulnerable Software and Affected Versions Neat VNC versions prior to 0.9.6

Description A pre-authentication stack buffer overflow exists in the RSA-AES security type handler. An unauthenticated remote attacker can send a crafted security type 5 (RSA-AES) or security type 129 (RSA-AES-256) handshake containing an oversized client RSA public key. This causes the rsa aes send challenge() function in src/auth/rsa-aes.c to overflow a 1024-byte on-stack buffer during the encryption of the server challenge, leading to a denial of service via a server crash.

Recommendations Update to version 0.9.6.