{"id":"GHSA-qw65-cvwx-89v3","summary":"fast-uri vulnerable to authority injection via an unvalidated port in serialize","details":"### Impact\n\n`fast-uri` serializes the `port` component of a URI without validating it. When recomposing the authority, `fast-uri` escapes the userinfo and host components but concatenates the port verbatim, so a `port` value that is not a sequence of digits can inject authority delimiters. For example, serializing a component whose `port` is `@127.0.0.1:8124` produces `http://trusted.example:@127.0.0.1:8124/app`, demoting the intended host to userinfo and pointing the authority at an attacker-controlled host. Both `fast-uri` and Node's `URL` read the result back as the attacker's host with no error, so re-validating the built URI does not catch it.\n\nThis affects applications that build URIs from parts and assign untrusted data to the `port` component (for example a fixed host from configuration and a port taken from user input or a service record). The same path is reachable through `serialize()`, `normalize()`, and `equal()` in their object forms. A `port` obtained from `parse()` is always digits and is not affected.\n\n### Patches\n\nThis vulnerability has been patched in fast-uri `4.1.4`, `3.1.7`, and `2.4.6`. `recomposeAuthority` now rejects any port that is not `*DIGIT` per RFC 3986. All users should upgrade.\n\n### Workarounds\n\nIf upgrading is not immediately possible, validate the `port` value against the RFC 3986 grammar (digits only) before passing a component to `serialize()`, `normalize()`, or `equal()`, and reject anything else, for example `if (!/^\\d*$/.test(String(port))) throw new Error('invalid port')`.","aliases":["CVE-2026-84292"],"modified":"2026-09-28T21:45:03.859117836Z","published":"2026-09-28T21:24:39Z","database_specific":{"github_reviewed_at":"2026-09-28T21:24:39Z","nvd_published_at":"2026-09-02T20:17:39Z","cwe_ids":["CWE-116"],"severity":"HIGH","github_reviewed":true},"references":[{"type":"WEB","url":"https://github.com/fastify/fast-uri/security/advisories/GHSA-qw65-cvwx-89v3"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-84292"},{"type":"WEB","url":"https://github.com/fastify/fast-uri/commit/820e8478dd7da3d09f187bfaf35d50b71f67b8b4"},{"type":"WEB","url":"https://cna.openjsf.org/security-advisories.html"},{"type":"PACKAGE","url":"https://github.com/fastify/fast-uri"},{"type":"WEB","url":"https://github.com/fastify/fast-uri/releases/tag/v2.4.6"},{"type":"WEB","url":"https://github.com/fastify/fast-uri/releases/tag/v3.1.7"},{"type":"WEB","url":"https://github.com/fastify/fast-uri/releases/tag/v4.1.4"}],"affected":[{"package":{"name":"fast-uri","ecosystem":"npm","purl":"pkg:npm/fast-uri"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.4.6"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-qw65-cvwx-89v3/GHSA-qw65-cvwx-89v3.json"}},{"package":{"name":"fast-uri","ecosystem":"npm","purl":"pkg:npm/fast-uri"},"ranges":[{"type":"SEMVER","events":[{"introduced":"3.0.0"},{"fixed":"3.1.7"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-qw65-cvwx-89v3/GHSA-qw65-cvwx-89v3.json"}},{"package":{"name":"fast-uri","ecosystem":"npm","purl":"pkg:npm/fast-uri"},"ranges":[{"type":"SEMVER","events":[{"introduced":"4.0.0"},{"fixed":"4.1.4"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-qw65-cvwx-89v3/GHSA-qw65-cvwx-89v3.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"}]}