{"cve":"CVE-2026-110306","nvd":{"published":"2026-10-20T07:17:08.810","modified":"2026-10-20T20:17:14.917","status":"Awaiting Analysis","description":"fast-uri is a dependency-free RFC 3986 URI parser and serializer for Node.js. In versions before 2.4.8, from 3.0.0 through 3.1.8, and from 4.0.0 through 4.2.2, fast-uri percent-decodes the scheme component with the legacy global unescape() function before validating it, so an input whose decoded scheme is a dangerous token is emitted as a live scheme even though RFC 3986 does not allow percent-encoding in a scheme and no other parser accepts it. An application that screens dangerous schemes on the raw input and then stores or renders the normalized or resolved result can turn an inert string into an executable javascript, data, or vbscript URL, producing a stored or reflected cross-site scripting vector, and the equal() comparison treats an encoded and a plain scheme as the same, which can bypass equality-based allowlists. The issue is fixed in fast-uri 2.4.8, 3.1.9, and 4.2.3, and users should upgrade to one of these versions or later. As a workaround, reject input whose scheme part contains a percent sign, or check the parsed scheme against an allowlist after normalization and use that same parsed result rather than the raw string.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1},"cwes":["CWE-172","CWE-180"],"references":["https://cna.openjsf.org/security-advisories.html","https://github.com/fastify/fast-uri/security/advisories/GHSA-w74x-v6f9-j3xg"],"products":[],"source":"nvd","synced_at":"2026-10-21T03:56:58.798400159+00:00"},"epss":{"cve":"CVE-2026-110306","score":0.0025,"percentile":0.16142,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-w74x-v6f9-j3xg","url":"https://osv.dev/vulnerability/GHSA-w74x-v6f9-j3xg","summary":"fast-uri vulnerable to URI scheme spoofing via percent-encoded scheme decoding","modified":"2026-10-23T21:45:04.896137439Z","packages":[{"ecosystem":"npm","name":"fast-uri","purl":"pkg:npm/fast-uri","ranges":["<2.4.8"],"fixed":["2.4.8"]},{"ecosystem":"npm","name":"fast-uri","purl":"pkg:npm/fast-uri","ranges":[">=3.0.0 <3.1.9"],"fixed":["3.1.9"]},{"ecosystem":"npm","name":"fast-uri","purl":"pkg:npm/fast-uri","ranges":[">=4.0.0 <4.2.3"],"fixed":["4.2.3"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}