{"id":"GHSA-f65p-4m7j-42xc","revision":"abf431b72a954a0c98edb9a2ccb5a350","records":[{"revision":"abf431b72a954a0c98edb9a2ccb5a350","observedAt":"2026-10-24T13:17:17.793+00:00","statement":{"source":"osv","id":"GHSA-f65p-4m7j-42xc","aliases":["CVE-2026-75975"],"title":"fast-uri vulnerable to server-side request forgery via malformed IPv6 normalization","description":"### Impact\n\n`fast-uri` does not validate the complete RFC 3986 grammar for bracketed IPv6 literals, so a malformed literal with invalid trailing text is silently truncated to a different valid IPv6 address with no error reported. For example, `normalize('http://[::not-valid]/private')` returns `http://[::]/private`, and `[fc00::not-hex]` and `[fe80::not-hex]` collapse to `[fc00::]` and `[fe80::]`. An application that normalizes an untrusted URL before an outbound request, redirect, or host-policy check can be routed to a local or private address such as loopback (`::1`), unique-local, or link-local. Because `parse().error` is unset for these inputs, checking it does not protect the consumer.\n\n### Patches\n\nUpgrade to `fast-uri` 2.4.5, 3.1.6, or 4.1.3. Malformed IPv6 literals are now rejected with a host error instead of being normalized to a valid address.\n\n### Workarounds\n\nReject untrusted URLs whose host is a bracketed IPv6 literal before passing them to `fast-uri`, or route outbound requests against an explicit allowlist of addresses rather than trusting the normalized host.","state":0,"publishedAt":"2026-09-02T15:43:30+00:00","modifiedAt":"2026-09-10T03:51:15.2924378+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-f65p-4m7j-42xc","https://nvd.nist.gov/vuln/detail/CVE-2026-75975","https://github.com/fastify/fast-uri/commit/3728465caacef4b16bc84b7d14760f1c8fe41595","https://github.com/fastify/fast-uri/commit/607bfbe953f28a14c2e06ae64aff38c81ca2937f","https://github.com/fastify/fast-uri/commit/9161eded1ff55fad9d9714c6ad6c0f0283547799","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-f65p-4m7j-42xc","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-f65p-4m7j-42xc","identifiers":["GHSA-f65p-4m7j-42xc","CVE-2026-75975"]},"retained":false,"historicalAffected":[]}],"coverage":[]}