{"schema":"threatline.record/2","record":{"id":"CVE-2021-20090","aliases":[],"summary":"Arcadyan Buffalo Firmware Path Traversal Vulnerability","details":"Arcadyan Buffalo firmware contains a path traversal vulnerability that could allow unauthenticated, remote attackers to bypass authentication and access sensitive information. This vulnerability affects multiple routers across several different vendors.","categories":["Unclassified"],"product":"Buffalo Firmware","vendor":"Arcadyan","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2021-20090","source_modified_at":"2025-10-21T23:25:47.628Z","fetched_at":"2026-10-23T18:42:43.628194Z","product":"Buffalo WSR-2533DHPL2, Buffalo WSR-2533DHP3","vendor":"n/a","versions":[{"version":"WSR-2533DHPL2 <=1.02, WSR-2533DHP3 <= 1.24","status":"affected"}],"defaultStatus":null}],"fixed_versions":[],"cvss":9.8,"severity":"Critical","kev":{"listed":true,"date_added":"2021-11-03","due_date":"2021-11-17","required_action":"Apply updates per vendor instructions.","ransomware_campaign_use":"Unknown"},"epss":{"probability":0.99982,"percentile":0.99982,"score_date":"2026-10-23"},"published_at":"2021-04-29T00:00:00.000Z","modified_at":"2025-10-21T23:25:47.628Z","provenance":[{"source":"CISA KEV","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23T17:00:09.9001Z"},{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2021-20090","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2025-10-21T23:25:47.628Z"},{"source":"Nuclei","url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-20090.yaml","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":null},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2021-20090","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CISA KEV","CVE List","Nuclei","EPSS"],"references":[{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-20090","source":"CISA KEV"},{"source":"CVE List","url":"https://www.tenable.com/security/research/tra-2021-13","tags":["x_transferred"]},{"source":"CVE List","url":"https://www.kb.cert.org/vuls/id/914124","tags":["third-party-advisory","x_transferred"]},{"source":"CVE List","url":"https://www.secpod.com/blog/arcadyan-based-routers-and-modems-under-active-exploitation/","tags":["x_transferred"]},{"source":"CVE List","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-20090","tags":["government-resource"]}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CISA ADP","ssvc":{"exploitation":"active","automatable":"yes","technical_impact":"total","assessed_at":"2025-02-06T20:25:22.891349Z"},"exploits":[{"source":"Nuclei","kind":"Scanner template","name":"Buffalo WSR-2533DHPL2 - Path Traversal","url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-20090.yaml"}],"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":null,"confidence":"unknown","reviewed":false},"change_timestamp":"2025-10-21T23:25:47.628Z","content_hash":"8818a6c6849966e2a0097eac7367eb3c1e5d48ada0f5fc9eba3fef0c2d1ceb5f"}}