CVE-2026-42859

EIP tracks 1 public exploit for CVE-2026-42859. PoCs published by exploitintel.

AI-analyzed exploit summary The repository contains a functional exploit PoC for CVE-2026-42859, a stack-based buffer overflow in neatvnc's RSA-AES authentication. The PoC demonstrates control-flow hijack by overflowing a 1024-byte stack buffer with attacker-controlled RSA key sizes, leading to RIP overwrite when stack canaries are disabled.

Neat VNC is a VNC server library. Prior to 0.9.6, a pre-authentication stack buffer overflow exists in neatvnc in the RSA-AES security type handler. An unauthenticated remote attacker who can reach the VNC listening socket can send a crafted security type 5 (RSA-AES) or security type 129 (RSA-AES-256) handshake with an oversized client RSA public key, causing rsa_aes_send_challenge in src/auth/rsa-aes.c to overflow a 1024-byte on-stack buffer when encrypting the server challenge. This results in at least a denial of service via server crash. This vulnerability is fixed in 0.9.6.