{"id":"GHSA-333x-w4r6-6crp","summary":"fast-uri vulnerable to scheme injection via an unescaped first-segment colon in suffix references","details":"### Impact\n\n`fast-uri`'s `serialize()`, `normalize()`, and `resolve()`, when called with the non-default option `reference: 'suffix'` on a reference that has no authority, emit a relative reference whose first path segment contains a bare colon without escaping it. RFC 3986 section 3.3 requires the first segment of a `path-noscheme` reference not to contain a colon, precisely because a bare colon makes the string reparse as an absolute URI with a scheme. `fast-uri`'s default serialization escapes that colon, but the suffix path does not.\n\nFor example, `normalize('javascript:alert(1)', { reference: 'suffix' })` returns `javascript:alert(1)`, which reparses as a live `javascript:` scheme; `data:` and `vbscript:` behave the same.\n\nApplications that serialize or normalize a relative reference with `reference: 'suffix'` and then treat the result as a URI can turn inert input into a live `javascript:`, `data:`, or `vbscript:` URL (a cross-site scripting vector), and `equal()` can conflate a scheme-bearing reference with a relative one. Exposure is limited to applications that use the non-default `reference: 'suffix'` option.\n\n### Patches\n\nUpgrade to `fast-uri` `2.4.8`, `3.1.9`, or `4.2.3`.\n\n### Workarounds\n\nDo not use the `reference: 'suffix'` option on untrusted input. If suffix output is required, percent-encode a colon in the first path segment of the result before treating it as a URI.","aliases":["CVE-2026-110725"],"modified":"2026-10-23T21:45:04.900311356Z","published":"2026-10-23T21:36:40Z","database_specific":{"github_reviewed":true,"github_reviewed_at":"2026-10-23T21:36:40Z","nvd_published_at":"2026-10-20T07:17:08Z","cwe_ids":["CWE-116","CWE-41"],"severity":"LOW"},"references":[{"type":"WEB","url":"https://github.com/fastify/fast-uri/security/advisories/GHSA-333x-w4r6-6crp"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-110725"},{"type":"WEB","url":"https://github.com/fastify/fast-uri/commit/39e6493c1356f30a0084171627eb266786e1620e"},{"type":"WEB","url":"https://github.com/fastify/fast-uri/commit/a9b8d67353630aab053cd727cf629023dd018d2b"},{"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/v2.4.8"},{"type":"WEB","url":"https://github.com/fastify/fast-uri/releases/tag/v3.1.9"},{"type":"WEB","url":"https://github.com/fastify/fast-uri/releases/tag/v4.2.3"}],"affected":[{"package":{"name":"fast-uri","ecosystem":"npm","purl":"pkg:npm/fast-uri"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.4.8"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-333x-w4r6-6crp/GHSA-333x-w4r6-6crp.json"}},{"package":{"name":"fast-uri","ecosystem":"npm","purl":"pkg:npm/fast-uri"},"ranges":[{"type":"SEMVER","events":[{"introduced":"3.0.0"},{"fixed":"3.1.9"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-333x-w4r6-6crp/GHSA-333x-w4r6-6crp.json"}},{"package":{"name":"fast-uri","ecosystem":"npm","purl":"pkg:npm/fast-uri"},"ranges":[{"type":"SEMVER","events":[{"introduced":"4.0.0"},{"fixed":"4.2.3"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-333x-w4r6-6crp/GHSA-333x-w4r6-6crp.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N"}]}