{"id":"CVE-2021-20090","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-20090","generatedAt":"2026-10-31T15:09:28.358Z","title":"Arcadyan Buffalo Firmware Path Traversal Vulnerability","description":"A path traversal vulnerability in the web interfaces of Buffalo WSR-2533DHPL2 firmware version <= 1.02 and WSR-2533DHP3 firmware version <= 1.24 could allow unauthenticated remote attackers to bypass authentication.","published":"2021-04-29T15:15:11.000Z","lastModified":"2026-06-17T03:33:15.000Z","status":"Analyzed","sourceIdentifier":"vulnreport@tenable.com","cvss":{"version":"3.1","score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-22"],"affected":["buffalo/wsr-2533dhpl2-bk firmware","buffalo/wsr-2533dhp3-bk firmware"],"epss":{"score":0.99982,"percentile":0.99982,"date":"2026-10-30","history":[]},"kev":{"listed":true,"dateAdded":"2021-11-03","dueDate":"2021-11-17","knownRansomwareCampaignUse":"Unknown","notes":"Apply updates per vendor instructions.\nhttps://nvd.nist.gov/vuln/detail/CVE-2021-20090"},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"Known to be exploited in the wild (CISA KEV, CISA remediation deadline 17 November 2021). Treat as an emergency change: patch or isolate now, then hunt for prior compromise."},"changes":[],"references":[{"url":"https://www.kb.cert.org/vuls/id/914124","tags":["Third Party Advisory","US Government Resource"],"source":"vulnreport@tenable.com"},{"url":"https://www.secpod.com/blog/arcadyan-based-routers-and-modems-under-active-exploitation/","tags":["Exploit","Third Party Advisory"],"source":"vulnreport@tenable.com"},{"url":"https://www.tenable.com/security/research/tra-2021-13","tags":["Exploit","Third Party Advisory"],"source":"vulnreport@tenable.com"},{"url":"https://www.kb.cert.org/vuls/id/914124","tags":["Third Party Advisory","US Government Resource"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.secpod.com/blog/arcadyan-based-routers-and-modems-under-active-exploitation/","tags":["Exploit","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.tenable.com/security/research/tra-2021-13","tags":["Exploit","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-20090","tags":["US Government Resource"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-20090","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}