{"id":"GHSA-5jgf-p345-68v8","revision":"69c07c9aecd54075b05c40b6af2a7702","records":[{"revision":"69c07c9aecd54075b05c40b6af2a7702","observedAt":"2026-10-24T13:17:17.793+00:00","statement":{"source":"osv","id":"GHSA-5jgf-p345-68v8","aliases":["CVE-2026-75931"],"title":"fast-uri vulnerable to host confusion via skipped IDN canonicalization on scheme-relative references","description":"### Impact\n\n`fast-uri` canonicalizes a host to its ASCII form only when the input carries an explicit scheme. When `resolve()` resolves a scheme-relative reference (`//host/`) against a scheme-bearing base, it still emits the host verbatim even though the effective scheme is known, so re-parsing the resolved URI yields a different host than the one `resolve()` returned. An application that resolves an untrusted reference with `fast-uri` and then checks or routes on the resulting host can make a policy decision on one host and reach another. This is an incomplete-fix variant of CVE-2026-13676, whose IDN canonicalization was applied only to the scheme-bearing form.\n\n### Patches\n\nUpgrade to `fast-uri` 2.4.5, 3.1.6, or 4.1.3. `resolve()` now canonicalizes the host once the effective scheme is known, and fails closed if a raw non-ASCII host cannot be converted.\n\n### Workarounds\n\nResolve scheme-relative references against a base that carries a scheme before performing any host-policy or origin check.","state":0,"publishedAt":"2026-09-02T15:44:30+00:00","modifiedAt":"2026-09-10T03:51:15.0836817+00:00","affected":[{"ecosystem":"npm","name":"fast-uri","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"2.4.2"},{"kind":"fixed","version":"2.4.5"}]}],"versions":[],"rawVersionEvidence":null},{"ecosystem":"npm","name":"fast-uri","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"3.1.3"},{"kind":"fixed","version":"3.1.6"}]}],"versions":[],"rawVersionEvidence":null},{"ecosystem":"npm","name":"fast-uri","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"4.0.1"},{"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-5jgf-p345-68v8","https://nvd.nist.gov/vuln/detail/CVE-2026-75931","https://github.com/fastify/fast-uri/commit/0256bc8d1f28b5d0ac657faf67e2411a189dfcb5","https://github.com/fastify/fast-uri/commit/444ecdad447db2cc23c4d422acc6f0daa6fa8eef","https://github.com/fastify/fast-uri/commit/4e4ebd8b245f6ca16e448203559eea3e545453a3","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-5jgf-p345-68v8","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-5jgf-p345-68v8","identifiers":["GHSA-5jgf-p345-68v8","CVE-2026-75931"]},"retained":false,"historicalAffected":[]}],"coverage":[]}