ADVISORY

HIGH: fast-uri — fast-uri vulnerable to host confusion via backslash authority introducer

Impact fast-uri v4.1.1 and earlier require a literal // to recognize a URI authority, so a reference that uses \\, /\, or \/ as the authority introducer (in place of //, after an optional scheme) is parsed with no authority: the sequence and everything…

Source fast-uriPublished 9h ago · Aug 3, 2026Posted on Threads

What we hold

Package
fast-uri
Ecosystem
npm
Severity
HIGH
ID
CVE-2026-18446

Impact fast-uri v4.1.1 and earlier require a literal // to recognize a URI authority, so a reference that uses \\, /\, or \/ as the authority introducer (in place of //, after an optional scheme) is parsed with no authority: the sequence and everything…