{"id":"CVE-2021-20021","kind":"vulnerability","aliases":["CVE-2021-20021"],"related":[],"title":"SonicWall SonicWall Email Security: SonicWall Email Security Improper Privilege Management Vulnerability","description":"SonicWall Email Security contains an improper privilege management vulnerability that allows an attacker to create an administrative account by sending a crafted HTTP request to the remote host. This vulnerability has known usage in a SonicWall Email Security exploit chain along with CVE-2021-20022 and CVE-2021-20023 to achieve privilege escalation.\n\nCISA required action: Apply updates per vendor instructions.","summary":"SonicWall Email Security has an improper privilege management flaw that lets an unauthenticated attacker create an administrator account by sending a crafted HTTP request. It is known to be used in a real exploit chain with CVE-2021-20022 and CVE-2021-20023 for privilege escalation.","severity":"critical","cvss":9.8,"epss":0.8878,"exploited":true,"exploited_at":"2021-11-03T00:00:00+00:00","products":[{"name":"SonicWall SonicWall Email Security","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["email-security","exploited","ransomware","self-hosted","sonicwall","vendor"],"not_affected_if":["unknown"],"how_to_check":null,"fix":"Apply the vendor's updates per SonicWall instructions; exact fixed version unknown from sources.","status":"open","published_at":"2021-04-09T18:15:13+00:00","first_seen_at":"2026-10-23T19:11:53+00:00","triaged_at":"2026-10-23T21:41:23+00:00","updated_at":"2026-10-23T21:57:34+00:00","category":"vendor","confidence":0.7,"triage":{"at":"2026-10-23T21:41:23Z","model":"claude-haiku-5-5","output":{"fix":"Apply the vendor's updates per SonicWall instructions; exact fixed version unknown from sources.","reach":"internet","impact":"high","summary":"SonicWall Email Security has an improper privilege management flaw that lets an unauthenticated attacker create an administrator account by sending a crafted HTTP request. It is known to be used in a real exploit chain with CVE-2021-20022 and CVE-2021-20023 for privilege escalation.","category":"vendor","who_cares":["sonicwall","email-security","self-hosted"],"confidence":0.7,"needs_auth":"no","worst_case":"Attacker creates an admin account and takes over the email security appliance.","analyst_note":"Find affected and fixed version ranges and an admin-account audit method in the SonicWall advisory for CVE-2021-20021 (not in the sources given).","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["unknown"],"user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"critical"},"cost_usd":0.000472,"input_tokens":2912,"output_tokens":362,"severity_before":"unknown"},"analyst_status":"queued","analyst_note":"Find affected and fixed version ranges and an admin-account audit method in the SonicWall advisory for CVE-2021-20021 (not in the sources given).","search":"'-20021':14A,17A '-20022':70B,122C '-20023':74B,126C '-2021':13A,16A,69B,73B,121C,125C 'account':49B,95C 'achiev':128C 'action':133C 'administr':48B,94C 'allow':88C 'along':118C 'appli':134C 'attack':45B,90C 'chain':66B,117C 'cisa':131C 'contain':81C 'craft':53B,99C 'creat':46B,92C 'cve':12A,15A,68B,72B,120C,124C 'email':3A,6A,20A,23B,33B,79C,114C 'email-secur':22B 'escal':77B,130C 'exploit':25B,65B,116C 'flaw':40B 'host':29B,105C 'http':54B,100C 'improp':8A,37B,83C 'instruct':138C 'known':58B,109C 'let':42B 'manag':10A,39B,85C 'per':136C 'privileg':9A,38B,76B,84C,129C 'ransomwar':26B 'real':64B 'remot':104C 'request':55B,101C 'requir':132C 'secur':4A,7A,24B,34B,80C,115C 'security':21A 'self':28B 'self-host':27B 'send':51B,97C 'sonicwal':1A,2A,5A,30B,32B,78C,113C 'sonicwall':18A,19A 'unauthent':44B 'updat':135C 'usag':110C 'use':61B 'vendor':31B,137C 'vulner':11A,86C,107C","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2021-04-09T18:15:13+00:00","kev":{"dateAdded":"2021-11-03","dueDate":"2021-11-17","requiredAction":"Apply updates per vendor instructions.","knownRansomwareCampaignUse":"Known"},"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvss_by":"nvd@nist.gov","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2021-20021","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-20021","severity":null,"published_at":"2021-11-03T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:53+00:00","fetched_at":"2026-10-25T10:39:08+00:00","note":null},{"source":"epss","external_id":"CVE-2021-20021","url":"https://api.first.org/data/v1/epss?cve=CVE-2021-20021","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-23T19:13:43+00:00","fetched_at":"2026-10-23T19:13:43+00:00","note":null},{"source":"nvd","external_id":"CVE-2021-20021","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-20021","severity":null,"published_at":"2021-04-09T18:15:13+00:00","modified_at":"2026-08-12T05:17:33+00:00","first_seen_at":"2026-10-23T21:57:34+00:00","fetched_at":"2026-10-23T21:57:34+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}