{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-67191","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","state":"PUBLISHED","assignerShortName":"VulnCheck","dateReserved":"2026-07-28T16:06:49.773Z","datePublished":"2026-07-29T15:50:53.320Z","dateUpdated":"2026-08-14T16:50:47.374Z"},"containers":{"cna":{"providerMetadata":{"orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","shortName":"VulnCheck","dateUpdated":"2026-08-14T16:50:47.374Z"},"title":"Xlight FTP Server < 3.9.5 Pre-Auth Heap Buffer Overflow via SSH Parser","descriptions":[{"lang":"en","value":"Xlight FTP Server before 3.9.5 contains a pre-authentication heap buffer overflow vulnerability that allows remote unauthenticated attackers to write past the end of a heap buffer by sending a malformed SSH client identification string. A logic error in the recv loop's termination condition uses an incorrect OR operator where an AND operator is required, enabling exploitation on any SSH or SFTP connection before authentication occurs."}],"datePublic":"2026-07-01T00:00:00.000Z","problemTypes":[{"descriptions":[{"lang":"en","cweId":"CWE-122","description":"Heap-based Buffer Overflow","type":"CWE"}]}],"affected":[{"defaultStatus":"affected","vendor":"Xlight","product":"Xlight FTP Server","versions":[{"status":"affected","version":"0","versionType":"semver","lessThan":"3.9.5"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:xlightftpd:xlight_ftp_server:*:*:*:*:*:*:*:*","versionEndExcluding":"3.9.5"}]}]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"HIGH","subIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","version":"4.0","baseSeverity":"CRITICAL","baseScore":9.3,"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"}},{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH","version":"3.1","baseSeverity":"CRITICAL","baseScore":9.8,"vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}}],"references":[{"url":"https://www.xlightftpd.com/whatsnew.htm","name":"Changelog","tags":["release-notes"]},{"url":"https://www.vulncheck.com/advisories/xlight-ftp-server-pre-auth-heap-buffer-overflow-via-ssh-parser","tags":["third-party-advisory"]}],"credits":[{"lang":"en","value":"McCaulay Hudson (@_McCaulay) of watchTowr","type":"finder"}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"vulncheck"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-29T16:32:16.525609Z","id":"CVE-2026-67191","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-07-29T16:32:49.768Z"}}]}}