{"id":"CVE-2021-20023","kind":"vulnerability","aliases":["CVE-2021-20023"],"related":[],"title":"SonicWall SonicWall Email Security: SonicWall Email Security Path Traversal Vulnerability","description":"SonicWall Email Security contains a path traversal vulnerability that allows a post-authenticated attacker to read files on the remote host. This vulnerability has known usage in a SonicWall Email Security exploit chain along with CVE-2021-20021 and CVE-2021-20022 to achieve privilege escalation.\n\nCISA required action: Apply updates per vendor instructions.","summary":"SonicWall Email Security has a path traversal flaw that lets a logged-in attacker read arbitrary files on the server. Attackers have used it in a chain with CVE-2021-20021 and CVE-2021-20022 to escalate privileges.","severity":"high","cvss":4.9,"epss":0.51689,"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 update per SonicWall instructions; exact fixed version not stated in sources.","status":"open","published_at":"2021-04-20T12:15:12+00:00","first_seen_at":"2026-10-23T19:11:53+00:00","triaged_at":"2026-10-23T21:43:24+00:00","updated_at":"2026-10-23T21:57:34+00:00","category":"vendor","confidence":0.7,"triage":{"at":"2026-10-23T21:43:24Z","model":"claude-haiku-5-5","output":{"fix":"Apply the vendor update per SonicWall instructions; exact fixed version not stated in sources.","reach":"internet","impact":"high","summary":"SonicWall Email Security has a path traversal flaw that lets a logged-in attacker read arbitrary files on the server. Attackers have used it in a chain with CVE-2021-20021 and CVE-2021-20022 to escalate privileges.","category":"vendor","who_cares":["sonicwall","email-security","self-hosted"],"confidence":0.7,"needs_auth":"yes","worst_case":"Attacker reads server files and escalates privileges, exposing secrets and credentials.","analyst_note":"Find the fixed version and affected build range in the SonicWall advisory for CVE-2021-20023 and a file or log indicator of exploitation.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["unknown"],"user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000463,"input_tokens":2897,"output_tokens":347,"severity_before":"unknown"},"analyst_status":"queued","analyst_note":"Find the fixed version and affected build range in the SonicWall advisory for CVE-2021-20023 and a file or log indicator of exploitation.","search":"'-20021':62B,108C '-20022':66B,112C '-20023':13A,16A '-2021':12A,15A,61B,65B,107C,111C 'achiev':114C 'action':119C 'allow':79C 'along':104C 'appli':120C 'arbitrari':47B 'attack':45B,52B,84C 'authent':83C 'chain':58B,103C 'cisa':117C 'contain':73C 'cve':11A,14A,60B,64B,106C,110C 'email':3A,6A,19A,22B,32B,71C,100C 'email-secur':21B 'escal':68B,116C 'exploit':24B,102C 'file':48B,87C 'flaw':38B 'host':28B,91C 'instruct':124C 'known':95C 'let':40B 'log':43B 'logged-in':42B 'path':8A,36B,75C 'per':122C 'post':82C 'post-authent':81C 'privileg':69B,115C 'ransomwar':25B 'read':46B,86C 'remot':90C 'requir':118C 'secur':4A,7A,23B,33B,72C,101C 'security':20A 'self':27B 'self-host':26B 'server':51B 'sonicwal':1A,2A,5A,29B,31B,70C,99C 'sonicwall':17A,18A 'travers':9A,37B,76C 'updat':121C 'usag':96C 'use':54B 'vendor':30B,123C 'vulner':10A,77C,93C","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2021-04-20T12:15:12+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:H/UI:N/S:U/C:H/I:N/A:N","cvss_by":"nvd@nist.gov","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2021-20023","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-20023","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-2021-20023","url":"https://api.first.org/data/v1/epss?cve=CVE-2021-20023","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-2021-20023","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-20023","severity":null,"published_at":"2021-04-20T12:15:12+00:00","modified_at":"2026-10-01T21:17:16+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"}