GitHub Advisoryadvisory · npm

GHSA-xhq7-xmqj-769h fast-uri vulnerable to improper path equivalence in relative reference normalization

LOW Published 2026-10-23 Modified 2026-10-23 Official page ↗
Aliases
CVE-2026-110095
Ecosystem
npm
Packages
fast-uri
Severity
Low
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Weaknesses
CWE-41
Reviewed
2026-10-23

Affected packages

• npm fast-uri: < 2.4.8 → fixed in 2.4.8 • npm fast-uri: >= 3.0.0, < 3.1.9 → fixed in 3.1.9 • npm fast-uri: >= 4.0.0, < 4.2.3 → fixed in 4.2.3

Description

Impact `fast-uri`'s `normalize()` and `serialize()` apply RFC 3986 dot-segment removal (`remove_dot_segments`) to the path of a relative-path reference. RFC 3986 section 5.2.4 defines that algorithm only for the merged target path during resolution, not for the reference itself, so applied to the reference it drops leading `..` segments and can turn a document-relative reference into a root-relative one. For example, `normalize('a/../b')` returns `/b` and `normalize('../x')` returns `x`, so `resolve(base, normalize(ref))` points at a different resource than `resolve(base, ref)`, and `equal()` treats distinct references as the same. Applications that normalize attacker-supplied or user-supplied relative references and then resolve them, or use them as cache, deduplication, or authorization keys, can have a reference escape its intended directory and point at a different resource. Patches Upgrade to `fast-uri` `2.4.8`, `3.1.9`, or `4.2.3`. Workarounds Do not normalize a relative reference before resolving it. Resolve it against the absolute base first, then normalize the absolute result.

Related

Alias · CVE (1)

  • CVE-2026-110095 fast-uri is a dependency-free RFC 3986 URI parser and serializer for Node.js. vulnerability

Weakness · CWE (1)

  • CWE-41 Improper Resolution of Path Equivalence weakness

References