{"schema":"threatline.record/2","record":{"id":"CVE-2026-110306","aliases":["GHSA-w74x-v6f9-j3xg"],"summary":"fast-uri vulnerable to URI scheme spoofing via percent-encoded scheme decoding","details":"### Impact\n\n`fast-uri` percent-decodes the scheme component with the legacy global `unescape()` before validating it, so an input whose decoded scheme is a valid but dangerous token is emitted as a live scheme. RFC 3986 section 3.1 does not allow percent-encoding in a scheme, so no RFC or WHATWG parser treats such input as having that scheme, but `fast-uri` does.\n\nFor example, `normalize('%6Aavascript:alert(1)')` returns `javascript:alert(1)`, `resolve('https://a.example/', '%6Aavascript:alert(1)')` returns `javascript:alert(1)`, and `parse('%6Aavascript:alert(1)').scheme` returns `javascript`. The `%uXXXX` form (`%u006Aavascript:`) produces the same result, and `equal('%68ttp://a/', 'http://a/')` returns `true`.\n\nAn application that screens dangerous schemes on the raw input and then stores or renders `normalize(input)` or `resolve(base, input)` turns an inert string into an executable `javascript:`, `data:`, or `vbscript:` URL, a stored or reflected cross-site scripting vector in the consuming application. `equal()` also treats an encoded and a plain scheme as the same, which can bypass equality-based allowlists.\n\n### Patches\n\nUpgrade to `fast-uri` `2.4.8`, `3.1.9`, or `4.2.3`.\n\n### Workarounds\n\nReject input whose scheme part (before the first `:`, and before any `/`, `?`, or `#`) contains `%`. Alternatively, check `parse(x).scheme` against an allowlist after normalization and use that same parsed result rather than the raw string.","categories":["Libraries & packages"],"product":"fast-uri","vendor":"fast-uri","ecosystem":"npm","affected_ranges":[{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-w74x-v6f9-j3xg","source_modified_at":"2026-10-23T21:41:38Z","fetched_at":"2026-10-23T21:47:51.402276Z","package":{"ecosystem":"npm","name":"fast-uri"},"range":"< 2.4.8"},{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-w74x-v6f9-j3xg","source_modified_at":"2026-10-23T21:41:38Z","fetched_at":"2026-10-23T21:47:51.402276Z","package":{"ecosystem":"npm","name":"fast-uri"},"range":">= 3.0.0, < 3.1.9"},{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-w74x-v6f9-j3xg","source_modified_at":"2026-10-23T21:41:38Z","fetched_at":"2026-10-23T21:47:51.402276Z","package":{"ecosystem":"npm","name":"fast-uri"},"range":">= 4.0.0, < 4.2.3"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-110306","source_modified_at":"2026-10-20T19:14:13.871Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"fast-uri","vendor":"fast-uri","versions":[{"lessThan":"2.4.8","status":"affected","version":"0","versionType":"semver"},{"status":"unaffected","version":"2.4.8","versionType":"semver"},{"lessThan":"3.1.9","status":"affected","version":"3.0.0","versionType":"semver"},{"status":"unaffected","version":"3.1.9","versionType":"semver"},{"lessThan":"4.2.3","status":"affected","version":"4.0.0","versionType":"semver"},{"status":"unaffected","version":"4.2.3","versionType":"semver"}],"defaultStatus":"unaffected"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-w74x-v6f9-j3xg","source_modified_at":"2026-10-23T21:45:04.896137439Z","fetched_at":"2026-10-23T21:47:51.402276Z","package":{"name":"fast-uri","ecosystem":"npm","purl":"pkg:npm/fast-uri"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.4.8"}]}],"versions":[]},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-w74x-v6f9-j3xg","source_modified_at":"2026-10-23T21:45:04.896137439Z","fetched_at":"2026-10-23T21:47:51.402276Z","package":{"name":"fast-uri","ecosystem":"npm","purl":"pkg:npm/fast-uri"},"ranges":[{"type":"SEMVER","events":[{"introduced":"3.0.0"},{"fixed":"3.1.9"}]}],"versions":[]},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-w74x-v6f9-j3xg","source_modified_at":"2026-10-23T21:45:04.896137439Z","fetched_at":"2026-10-23T21:47:51.402276Z","package":{"name":"fast-uri","ecosystem":"npm","purl":"pkg:npm/fast-uri"},"ranges":[{"type":"SEMVER","events":[{"introduced":"4.0.0"},{"fixed":"4.2.3"}]}],"versions":[]}],"fixed_versions":[{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-w74x-v6f9-j3xg","source_modified_at":"2026-10-23T21:41:38Z","fetched_at":"2026-10-23T21:47:51.402276Z","package":{"ecosystem":"npm","name":"fast-uri"},"version":"2.4.8"},{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-w74x-v6f9-j3xg","source_modified_at":"2026-10-23T21:41:38Z","fetched_at":"2026-10-23T21:47:51.402276Z","package":{"ecosystem":"npm","name":"fast-uri"},"version":"3.1.9"},{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-w74x-v6f9-j3xg","source_modified_at":"2026-10-23T21:41:38Z","fetched_at":"2026-10-23T21:47:51.402276Z","package":{"ecosystem":"npm","name":"fast-uri"},"version":"4.2.3"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-110306","source_modified_at":"2026-10-20T19:14:13.871Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"fast-uri","ecosystem":null},"version":"2.4.8","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-110306","source_modified_at":"2026-10-20T19:14:13.871Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"fast-uri","ecosystem":null},"version":"3.1.9","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-110306","source_modified_at":"2026-10-20T19:14:13.871Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"fast-uri","ecosystem":null},"version":"4.2.3","basis":"first unaffected version stated in the CVE record"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-w74x-v6f9-j3xg","source_modified_at":"2026-10-23T21:45:04.896137439Z","fetched_at":"2026-10-23T21:47:51.402276Z","package":{"name":"fast-uri","ecosystem":"npm","purl":"pkg:npm/fast-uri"},"version":"2.4.8"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-w74x-v6f9-j3xg","source_modified_at":"2026-10-23T21:45:04.896137439Z","fetched_at":"2026-10-23T21:47:51.402276Z","package":{"name":"fast-uri","ecosystem":"npm","purl":"pkg:npm/fast-uri"},"version":"3.1.9"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-w74x-v6f9-j3xg","source_modified_at":"2026-10-23T21:45:04.896137439Z","fetched_at":"2026-10-23T21:47:51.402276Z","package":{"name":"fast-uri","ecosystem":"npm","purl":"pkg:npm/fast-uri"},"version":"4.2.3"}],"cvss":6.1,"severity":"Medium","kev":{"listed":false},"epss":{"probability":0.00204,"percentile":0.09881,"score_date":"2026-10-23"},"published_at":"2026-10-20T07:03:47.312Z","modified_at":"2026-10-23T21:45:04.896137439Z","provenance":[{"source":"GitHub Advisory Database","url":"https://github.com/advisories/GHSA-w74x-v6f9-j3xg","fetched_at":"2026-10-23T21:47:51.402276Z","source_modified_at":"2026-10-23T21:41:38Z"},{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-110306","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-20T19:14:13.871Z"},{"source":"OSV","url":"https://osv.dev/vulnerability/GHSA-w74x-v6f9-j3xg","fetched_at":"2026-10-23T21:47:51.402276Z","source_modified_at":"2026-10-23T21:45:04.896137439Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-110306","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["GitHub Advisory Database","CVE List","OSV","EPSS"],"references":[{"source":"CVE List","url":"https://github.com/fastify/fast-uri/security/advisories/GHSA-w74x-v6f9-j3xg"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-110306","source":"GitHub Advisory Database"},{"url":"https://github.com/fastify/fast-uri/commit/39933a1f1422986f14e2d844f552238feb40f5d4","source":"GitHub Advisory Database"},{"url":"https://github.com/fastify/fast-uri/commit/597f254c86d151568511eeb9a1df761fd12520b3","source":"GitHub Advisory Database"},{"url":"https://github.com/fastify/fast-uri/commit/e60e716f41d1d73717e2d803d20b68d2c6d20a0f","source":"GitHub Advisory Database"},{"source":"CVE List","url":"https://cna.openjsf.org/security-advisories.html"},{"url":"https://github.com/fastify/fast-uri/releases/tag/v2.4.8","source":"GitHub Advisory Database"},{"url":"https://github.com/fastify/fast-uri/releases/tag/v3.1.9","source":"GitHub Advisory Database"},{"url":"https://github.com/fastify/fast-uri/releases/tag/v4.2.3","source":"GitHub Advisory Database"},{"url":"https://github.com/advisories/GHSA-w74x-v6f9-j3xg","source":"GitHub Advisory Database"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","ssvc":{"exploitation":"none","automatable":"no","technical_impact":"partial","assessed_at":"2026-10-20T19:14:03.847725Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"ecosystem","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-23T21:45:04.896137439Z","content_hash":"62b3f263462eba4360ec8a022e81d30fb8e2f0494ff9a19219cd2d72c3224d3f"}}