{"id":"GHSA-c4qr-gmr9-v23w","summary":"Prefix escape","details":"### Impact\n\nBy crafting a specific URL, it is possible to escape the prefix of the proxied backend service.\nIf the base url of the proxied server is `/pub/`, a user expect that accessing `/priv` on the target service would not be possible. Unfortunately, it is.\n\n[CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N](https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N)\n\n### Patches\n\nAll releases after v4.3.1 include the fix.\n\n### Workarounds\n\nThere are no workaround available.\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [fastify-reply-from](https://github.com/fastify/fastify-reply-from)\n* Email us at [hello@matteocollina.com](mailto:hello@matteocollina.com)","aliases":["CVE-2021-21322"],"modified":"2026-07-08T06:28:05.180812220Z","published":"2021-03-03T02:18:08Z","database_specific":{"github_reviewed_at":"2021-03-02T03:32:25Z","nvd_published_at":"2021-03-02T04:15:00Z","cwe_ids":["CWE-20"],"severity":"LOW","github_reviewed":true},"references":[{"type":"WEB","url":"https://github.com/fastify/fastify-http-proxy/security/advisories/GHSA-c4qr-gmr9-v23w"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-21322"},{"type":"WEB","url":"https://github.com/fastify/fastify-http-proxy/commit/02d9b43c770aa16bc44470edecfaeb7c17985016"},{"type":"WEB","url":"https://www.npmjs.com/package/fastify-http-proxy"}],"affected":[{"package":{"name":"fastify-http-proxy","ecosystem":"npm","purl":"pkg:npm/fastify-http-proxy"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"4.3.1"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/03/GHSA-c4qr-gmr9-v23w/GHSA-c4qr-gmr9-v23w.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N"}]}