{"id":"CVE-2021-22964","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-22964","generatedAt":"2026-10-27T23:28:22.763Z","title":"A redirect vulnerability in the `fastify-static` module version >= 4.2.4 and < 4.4.1 allows remote attackers to redirect Mozilla Firefox users to arbitrary websites via a double slash `//` followed by a domain:…","description":"A redirect vulnerability in the `fastify-static` module version >= 4.2.4 and < 4.4.1 allows remote attackers to redirect Mozilla Firefox users to arbitrary websites via a double slash `//` followed by a domain: `http://localhost:3000//a//youtube.com/%2e%2e%2f%2e%2e`.A DOS vulnerability is possible if the URL contains invalid characters `curl --path-as-is \"http://localhost:3000//^/..\"`The issue shows up on all the `fastify-static` applications that set `redirect: true` option. By default, it is `false`.","published":"2021-10-14T15:15:09.000Z","lastModified":"2026-06-17T03:38:07.000Z","status":"Modified","sourceIdentifier":"support@hackerone.com","cvss":{"version":"3.1","score":8.8,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:H"},"cwe":["CWE-400","CWE-601"],"affected":["fastify/fastify-static"],"epss":{"score":0.01021,"percentile":0.63191,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (1.02%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://hackerone.com/reports/1361804","tags":["Exploit","Issue Tracking","Patch","Third Party Advisory"],"source":"support@hackerone.com"},{"url":"https://hackerone.com/reports/1361804","tags":["Exploit","Issue Tracking","Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-22964","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."}