{"id":"CVE-2021-20021","published":"2021-04-09T18:15:13Z","modified":"2026-08-12T05:17:33Z","title":"SonicWall Email Security Improper Privilege Management Vulnerability","vendor":"SonicWall","product":"SonicWall Email Security","tier":"core","eol":null,"description":{"text":"A vulnerability in the SonicWall Email Security version 10.0.9.x allows an attacker to create an administrative account by sending a crafted HTTP request to the remote host.","provenance":"source","from":"NVD"},"summary":{"text":"SonicWall Email Security contains an improper privilege management flaw, in which a crafted HTTP request can cause the system to create an administrative account. An attacker needs only network access to the remote host, with no authentication and no user interaction required.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-29T07:53:43Z"},"cvss":{"score":9.8,"severity":"CRITICAL","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","provenance":"source","from":"NVD"},"epss":{"score":0.8878,"percentile":0.99776,"date":"2026-10-31","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-2021-20021","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://www.mandiant.com/resources/blog/chinese-espionage-tactics","date":"2023-07-18"},{"url":"https://cisa.gov/news-events/cybersecurity-advisories/aa23-215a","date":"2023-08-03"}],"evidenceTotal":9,"provenance":"source"},"exploited":true,"otx":null,"cwes":[{"id":"CWE-269","name":"Improper Privilege Management"},{"id":"CWE-306","name":"Missing Authentication for Critical Functionality"}],"references":[{"url":"https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0007","tags":["Vendor Advisory"]},{"url":"https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0007","tags":["Vendor Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-20021","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: Crafted HTTP request to public-facing app","mappingType":"exploitation_technique","evidence":[{"from":"description","quote":"allows an attacker to create an administrative account by sending a crafted HTTP request","start":65,"end":153}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"},{"id":"T1136","name":"Create Account","tactics":["persistence"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: Creates new administrative account","mappingType":"primary_impact","evidence":[{"from":"description","quote":"allows an attacker to create an administrative account","start":65,"end":119}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2021-7484","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-7484","exploited":true,"exploitedSince":"2021-11-03","provenance":"source"},"exploits":[],"exploitSources":{"pocGithub":{"count":1,"skipped":0,"earliest":"2023-09-07","earliestUrl":"https://github.com/SUPRAAA-1337/CVE-2021-20021","repos":[{"name":"SUPRAAA-1337/CVE-2021-20021","url":"https://github.com/SUPRAAA-1337/CVE-2021-20021","stars":2,"created":"2023-09-07"}]},"nuclei":[{"id":"CVE-2021-20021","name":"SonicWall Email Security <= 10.0.9.x - Unauthenticated Admin Account Creation","severity":"critical","path":"http/cves/2021/CVE-2021-20021.yaml","url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-20021.yaml"}],"first":{"date":"2023-09-07","source":"PoC-in-GitHub","url":"https://github.com/SUPRAAA-1337/CVE-2021-20021"},"provenance":"source"},"exploitRefs":[],"flow":[{"stage":"exploitation","techniques":["T1190"],"provenance":"ai"},{"stage":"primary","techniques":["T1136"],"provenance":"ai"}],"timeline":[{"date":"2021-04-09","kind":"published","label":"Published (NVD)","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-20021","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 use)","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","provenance":"source"},{"date":"2021-11-03","kind":"euvd-exploited","label":"ENISA EUVD: exploited","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-7484","provenance":"source"},{"date":"2023-09-07","kind":"exploit-public","label":"First public exploit: PoC-in-GitHub","url":"https://github.com/SUPRAAA-1337/CVE-2021-20021","provenance":"source"}],"speed":{"daysToPublicExploit":881,"firstExploitFrom":"PoC-in-GitHub","daysToKev":208},"priority":{"score":76.8,"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 2021 days ago"},{"name":"Known ransomware use","points":10.0,"detail":"CISA KEV and VulnCheck KEV: Known"},{"name":"EPSS percentile","points":19.96,"detail":"percentile 0.9978"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":5.0,"detail":"1 PoC-in-GitHub repo; 1 nuclei template"},{"name":"Mentioned in OTX pulses","points":0.0,"detail":"0 pulses"},{"name":"CVSS severity","points":6.86,"detail":"base score 9.8"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]}}