{"cve":"CVE-2021-21322","nvd":{"published":"2021-03-02T04:15:12.597","modified":"2026-06-17T03:35:17.690","status":"Modified","description":"fastify-http-proxy is an npm package which is a fastify plugin for proxying your http requests to another server, with hooks. By crafting a specific URL, it is possible to escape the prefix of the proxied backend service. If the base url of the proxied server is `/pub/`, a user expect that accessing `/priv` on the target service would not be possible. In affected versions, it is possible. This is fixed in version 4.3.1.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":["CWE-20"],"references":["https://github.com/fastify/fastify-http-proxy/commit/02d9b43c770aa16bc44470edecfaeb7c17985016","https://github.com/fastify/fastify-http-proxy/security/advisories/GHSA-c4qr-gmr9-v23w","https://www.npmjs.com/package/fastify-http-proxy","https://github.com/fastify/fastify-http-proxy/commit/02d9b43c770aa16bc44470edecfaeb7c17985016","https://github.com/fastify/fastify-http-proxy/security/advisories/GHSA-c4qr-gmr9-v23w"],"products":["fastify-http-proxy_project:fastify-http-proxy"],"source":"nvd","synced_at":"2026-10-19T21:15:50.279857260+00:00"},"epss":{"cve":"CVE-2021-21322","score":0.01627,"percentile":0.76171,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-c4qr-gmr9-v23w","url":"https://osv.dev/vulnerability/GHSA-c4qr-gmr9-v23w","summary":"Prefix escape","modified":"2026-07-08T06:28:05.180812220Z","packages":[{"ecosystem":"npm","name":"fastify-http-proxy","purl":"pkg:npm/fastify-http-proxy","ranges":["<4.3.1"],"fixed":["4.3.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}