{"id":"GHSA-jqff-g426-hqxp","revision":"08726a121edf4578a5037de008fea776","records":[{"revision":"08726a121edf4578a5037de008fea776","observedAt":"2026-10-24T13:17:17.793+00:00","statement":{"source":"osv","id":"GHSA-jqff-g426-hqxp","aliases":["CVE-2026-76172"],"title":"fast-uri vulnerable to host confusion via percent-encoded scheme normalization","description":"### Impact\n\n`fast-uri` decodes percent-encoded characters in the scheme component with the legacy global `unescape()` and serializes the result back as raw characters, without re-escaping it or validating it as a scheme. A scheme that decodes to characters outside the RFC 3986 scheme grammar can therefore introduce structure the original input did not contain.\n\nFor example, `%2f%2fevil.example:/pwn` parses with no authority (`parse().host` is `undefined`), but `resolve()` and `normalize()` return `//evil.example:/pwn`, which reparses with host `evil.example`. The `%uXXXX` form (`%u002f%u002fevil.example:/pwn`) produces the same result, and a scheme containing `%0d%0a` reaches the output as a raw CR LF.\n\nApplications that normalize or resolve untrusted URLs before a redirect check, host allowlist, or outbound request decision, especially ones that treat a missing authority as same-origin, can be steered to an attacker-chosen authority, and a normalized URI placed in a response header can carry an injected CR LF.\n\n### Patches\n\nUpgrade to `fast-uri` >= 4.1.3, or >= 3.1.6 in the v3.x release line, or >= 2.4.5 in the v2.x release line.\n\n### Workarounds\n\nNone. Upgrade to the patched version.","state":0,"publishedAt":"2026-09-02T15:41:53+00:00","modifiedAt":"2026-09-10T03:50:54.4676625+00:00","affected":[{"ecosystem":"npm","name":"fast-uri","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"2.3.1"},{"kind":"fixed","version":"2.4.5"}]}],"versions":[],"rawVersionEvidence":null},{"ecosystem":"npm","name":"fast-uri","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"3.0.0"},{"kind":"fixed","version":"3.1.6"}]}],"versions":[],"rawVersionEvidence":null},{"ecosystem":"npm","name":"fast-uri","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"4.0.0"},{"kind":"fixed","version":"4.1.3"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"HIGH"}],"references":["https://github.com/fastify/fast-uri/security/advisories/GHSA-jqff-g426-hqxp","https://nvd.nist.gov/vuln/detail/CVE-2026-76172","https://github.com/fastify/fast-uri/commit/37f3417c82994279656854f83ce938acd81c3862","https://github.com/fastify/fast-uri/commit/a941e626411f576f8d90883231e57b6c9d0ff98b","https://github.com/fastify/fast-uri/commit/c6a74bfd9d8c6b0df5362b3c7ae88d8021cb1e39","https://cna.openjsf.org/security-advisories.html","https://github.com/fastify/fast-uri","https://github.com/fastify/fast-uri/releases/tag/v2.4.5","https://github.com/fastify/fast-uri/releases/tag/v3.1.6","https://github.com/fastify/fast-uri/releases/tag/v4.1.3"],"sourceUrl":"https://github.com/advisories/GHSA-jqff-g426-hqxp","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-jqff-g426-hqxp","identifiers":["GHSA-jqff-g426-hqxp","CVE-2026-76172"]},"retained":false,"historicalAffected":[]}],"coverage":[]}