CVE-2026-16221

Impact: fast-uri versions from 2.3.1 through 4.1.0 including the 3.x line up to 3.1.3 and the 2.x line up to 2.4.2 do not treat a literal backslash character U+005C as an authority delimiter. Node's native WHATWG URL parser, used by fetch, undici, and Node's http and https clients, normalizes the...

CVE-2026-16221

CVE-2026-16221 affects fast-uri versions 2.3.1–4.1.0 (including 3.x up to 3.1.3 and 2.x up to 2.4.2). The root cause is that a literal backslash (U+005C) is not treated as an authority delimiter, causing two URL parsers to extract different hosts from the same input. Node’s native WHATWG URL pars...