{"id":"CVE-2021-20023","published":"2021-04-20T12:15:12Z","modified":"2026-10-01T21:17:16Z","title":"SonicWall Email Security Path Traversal Vulnerability","vendor":"SonicWall","product":"SonicWall Email Security","tier":"core","eol":null,"description":{"text":"SonicWall Email Security version 10.0.9.x contains a vulnerability that allows a post-authenticated attacker to read an arbitrary file on the remote host.","provenance":"source","from":"NVD"},"summary":{"text":"SonicWall Email Security (version 10.0.9.x) contains a path traversal flaw, classified as improper limitation of a pathname to a restricted directory. An attacker who has already authenticated to the product can use it to read arbitrary files on the remote host, with no user interaction required.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-29T13:44:05Z"},"cvss":{"score":4.9,"severity":"MEDIUM","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N","provenance":"source","from":"NVD"},"epss":{"score":0.51689,"percentile":0.98944,"date":"2026-10-29","provenance":"source"},"kev":{"dateAdded":"2021-11-03","dueDate":"2021-11-17","ransomware":true,"requiredAction":"Apply updates per vendor instructions.","notes":"https://nvd.nist.gov/vuln/detail/CVE-2021-20023","provenance":"source"},"vulncheckKev":{"dateAdded":"2021-04-20","exploitedFirstSeen":"2021-04-20","ransomware":true,"evidence":[{"url":"https://cloud.google.com/blog/topics/threat-intelligence/zero-day-exploits-in-sonicwall-email-security-lead-to-compromise/","date":"2021-04-20"},{"url":"https://www.fireeye.com/blog/threat-research/2021/04/zero-day-exploits-in-sonicwall-email-security-lead-to-compromise.html","date":"2021-04-20"},{"url":"https://www.mandiant.com/resources/suspected-apt-actors-leverage-bypass-techniques-pulse-secure-zero-day","date":"2021-04-20"},{"url":"https://www.ic3.gov/Media/News/2021/211029.pdf","date":"2021-10-28"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2021-11-03"},{"url":"https://cybersecurityworks.com/howdymanage/uploads/file/Spotlight%20Report%20-%20Index%20Update%20Q2%20-%20Q3%20-%20Final%20Version_compressed.pdf","date":"2022-05-18"},{"url":"https://www.ivanti.com/resources/v/doc/pr-survey-report/ransomware-quarterly-indexreport_q2-q3","date":"2022-10-21"},{"url":"https://info.securin.io/hubfs/Securin%20Ransomware%20Report%202023.pdf","date":"2023-02-14"},{"url":"https://www.mandiant.com/resources/blog/chinese-espionage-tactics","date":"2023-07-18"}],"evidenceTotal":9,"provenance":"source"},"exploited":true,"otx":{"pulseCount":50,"pulses":[{"name":"Actively_Exploited_Kev | Oct 29, 2026","url":"https://otx.alienvault.com/pulse/6ae20c1db17e7057ae7d9ad1","created":"2026-10-28"},{"name":"Actively_Exploited_Kev | Oct 28, 2026","url":"https://otx.alienvault.com/pulse/6ae0ba7e0e2a97ff7b218819","created":"2026-10-27"},{"name":"Actively_Exploited_Kev | Oct 27, 2026","url":"https://otx.alienvault.com/pulse/6adf68b85c3e852f3c111d18","created":"2026-10-26"},{"name":"Actively_Exploited_Kev | Oct 24, 2026","url":"https://otx.alienvault.com/pulse/6adb740e397c3ad4799aa4cd","created":"2026-10-23"},{"name":"Actively_Exploited_Kev | Oct 23, 2026","url":"https://otx.alienvault.com/pulse/6ada236fcfba2dfa730ea482","created":"2026-10-22"},{"name":"Actively_Exploited_Kev | Oct 22, 2026","url":"https://otx.alienvault.com/pulse/6ad8d33a077cbb5cab524d80","created":"2026-10-21"},{"name":"Actively_Exploited_Kev | Oct 21, 2026","url":"https://otx.alienvault.com/pulse/6ad78130c4d1ac2be83a8b6d","created":"2026-10-20"},{"name":"Actively_Exploited_Kev | Oct 20, 2026","url":"https://otx.alienvault.com/pulse/6ad62f63c24a405a3423cc13","created":"2026-10-19"},{"name":"Actively_Exploited_Kev | Oct 19, 2026","url":"https://otx.alienvault.com/pulse/6ad4dda174e5797d0bd238b7","created":"2026-10-18"},{"name":"Actively_Exploited_Kev | Oct 18, 2026","url":"https://otx.alienvault.com/pulse/6ad38c22e1848f8189d1c121","created":"2026-10-17"}],"provenance":"machine"},"cwes":[{"id":"CWE-22","name":"Improper Limitation of a Pathname to a Restricted Directory"}],"references":[{"url":"https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0010","tags":["Vendor Advisory"]},{"url":"https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0010","tags":["Vendor Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-20023","tags":["US Government Resource"]}],"techniques":[{"id":"T1078","name":"Valid Accounts","tactics":["initial-access","persistence","privilege-escalation","stealth"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: Requires prior authenticated access to exploit","mappingType":"exploitation_technique","evidence":[{"from":"description","quote":"post-authenticated attacker to read an arbitrary file","start":81,"end":134}],"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 yields local data access","mappingType":"primary_impact","evidence":[{"from":"description","quote":"read an arbitrary file on the remote host","start":112,"end":153}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2021-7486","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-7486","exploited":true,"exploitedSince":"2021-11-03","provenance":"source"},"exploits":[],"exploitSources":null,"exploitRefs":[],"flow":[{"stage":"exploitation","techniques":["T1078"],"provenance":"ai"},{"stage":"primary","techniques":["T1005"],"provenance":"ai"}],"timeline":[{"date":"2021-04-20","kind":"published","label":"Published (NVD)","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-20023","provenance":"source"},{"date":"2021-04-20","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://cloud.google.com/blog/topics/threat-intelligence/zero-day-exploits-in-sonicwall-email-security-lead-to-compromise/","provenance":"source"},{"date":"2021-11-03","kind":"kev","label":"Added to CISA KEV (known ransomware 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product","points":0.0,"detail":"supported or unknown"}]}}