fast-uri vulnerable to URI scheme spoofing via percent-encoded scheme decoding

影響: npm:fast-uri < 2.4.8 → 2.4.8, npm:fast-uri >= 3.0.0, < 3.1.9 → 3.1.9, npm:fast-uri >= 4.0.0, < 4.2.3 → 4.2.3

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. For example, normalize('%6Aavascript:alert(1)') returns javascript:alert(1), resolve('https://a.example/', '%6Aavascript:alert(1)') returns javascript:…

Read on GitHub Advisory Database

On 10/24/2026, 06:41 AM, GitHub Advisory Database published "fast-uri vulnerable to URI scheme spoofing via percent-encoded scheme decoding" (type: Advisory). Severity is "Medium" (medium). Related technologies: JavaScript / Node.js. CVE: CVE-2026-110306.