{"id":"CVE-2021-20123","published":"2021-10-13T16:15:07Z","modified":"2026-06-17T03:33:18Z","title":"Draytek VigorConnect Path Traversal Vulnerability","vendor":"DrayTek","product":"VigorConnect","tier":"core","eol":null,"description":{"text":"A local file inclusion vulnerability exists in Draytek VigorConnect 1.6.0-B3 in the file download functionality of the DownloadFileServlet endpoint. An unauthenticated attacker could leverage this vulnerability to download arbitrary files from the underlying operating system with root privileges.","provenance":"source","from":"NVD"},"summary":{"text":"A path traversal flaw in the file download functionality of the DownloadFileServlet endpoint in DrayTek VigorConnect 1.6.0-B3 allows arbitrary files to be read from the underlying operating system. An unauthenticated attacker with network access can exploit it without user interaction, retrieving files with root privileges.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-31T04:54:40Z"},"cvss":{"score":7.5,"severity":"HIGH","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","provenance":"source","from":"NVD"},"epss":{"score":0.89654,"percentile":0.99788,"date":"2026-10-31","provenance":"source"},"kev":{"dateAdded":"2024-09-03","dueDate":"2024-09-24","ransomware":false,"requiredAction":"Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.","notes":"https://www.draytek.com/about/security-advisory/vigorconnect-software-security-vulnerability-(cve-2021-20123-cve-2021-20129); https://nvd.nist.gov/vuln/detail/CVE-2021-20123","provenance":"source"},"vulncheckKev":{"dateAdded":"2024-07-30","exploitedFirstSeen":"2024-07-30","ransomware":false,"evidence":[{"url":"https://fortiguard.fortinet.com/encyclopedia/ips/55752","date":"2024-07-30"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2024-09-03"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2024-09-04&host_type=src&vulnerability=cve-2021-20123","date":"2024-09-04"},{"url":"https://www.tenable.com/blog/cve-2021-20123-cve-2021-20124-draytek-vulnerabilities-discovered-by-tenable-research-added-to","date":"2024-09-09"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2024-09-18&host_type=src&vulnerability=cve-2021-20123","date":"2024-09-18"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2024-09-21&host_type=src&vulnerability=cve-2021-20123","date":"2024-09-21"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2024-09-22&host_type=src&vulnerability=cve-2021-20123","date":"2024-09-22"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2024-09-26&host_type=src&vulnerability=cve-2021-20123","date":"2024-09-26"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2024-09-27&host_type=src&vulnerability=cve-2021-20123","date":"2024-09-27"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2024-09-28&host_type=src&vulnerability=cve-2021-20123","date":"2024-09-28"}],"evidenceTotal":267,"provenance":"source"},"exploited":true,"otx":null,"cwes":[{"id":"CWE-22","name":"Improper Limitation of a Pathname to a Restricted Directory"}],"references":[{"url":"https://www.tenable.com/security/research/tra-2021-42","tags":["Exploit","Third Party Advisory"]},{"url":"https://www.tenable.com/security/research/tra-2021-42","tags":["Exploit","Third Party Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-20123","tags":["US Government Resource"]}],"techniques":[{"id":"T1190","name":"Exploit Public-Facing Application","tactics":["initial-access"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: Unauthenticated remote exploit of public-facing web endpoint","mappingType":"exploitation_technique","evidence":[{"from":"description","quote":"An unauthenticated attacker could leverage this vulnerability","start":149,"end":210}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"},{"id":"T1005","name":"Data from Local System","tactics":["collection"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: Arbitrary file read from local system","mappingType":"primary_impact","evidence":[{"from":"description","quote":"download arbitrary files from the underlying operating system","start":214,"end":275}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2021-7580","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-7580","exploited":true,"exploitedSince":"2024-09-03","provenance":"source"},"exploits":[],"exploitSources":{"nuclei":[{"id":"CVE-2021-20123","name":"Draytek VigorConnect 1.6.0-B - Local File Inclusion","severity":"high","path":"http/cves/2021/CVE-2021-20123.yaml","url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-20123.yaml"}],"provenance":"source"},"exploitRefs":["https://www.tenable.com/security/research/tra-2021-42"],"flow":[{"stage":"exploitation","techniques":["T1190"],"provenance":"ai"},{"stage":"primary","techniques":["T1005"],"provenance":"ai"}],"timeline":[{"date":"2021-10-13","kind":"published","label":"Published (NVD)","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-20123","provenance":"source"},{"date":"2024-07-30","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://fortiguard.fortinet.com/encyclopedia/ips/55752","provenance":"source"},{"date":"2024-09-03","kind":"kev","label":"Added to CISA KEV","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","provenance":"source"},{"date":"2024-09-03","kind":"euvd-exploited","label":"ENISA EUVD: exploited","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-7580","provenance":"source"}],"speed":{"daysToPublicExploit":null,"firstExploitFrom":null,"daysToKev":1056},"priority":{"score":65.2,"factors":[{"name":"In a KEV catalog","points":35.0,"detail":"listed in CISA KEV and VulnCheck KEV"},{"name":"Recent KEV listing","points":0.0,"detail":"added 824 days ago"},{"name":"Known ransomware use","points":0.0,"detail":"not known"},{"name":"EPSS percentile","points":19.96,"detail":"percentile 0.9979"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":5.0,"detail":"1 NVD reference tagged Exploit; 1 nuclei template"},{"name":"Mentioned in OTX pulses","points":0.0,"detail":"0 pulses"},{"name":"CVSS severity","points":5.25,"detail":"base score 7.5"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]}}