GitHub Advisoryadvisory · npm
GHSA-xhq7-xmqj-769h fast-uri vulnerable to improper path equivalence in relative reference normalization
LOW
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
- https://github.com/fastify/fast-uri/security/advisories/GHSA-xhq7-xmqj-769h web
- https://nvd.nist.gov/vuln/detail/CVE-2026-110095 advisory
- https://github.com/fastify/fast-uri/commit/048bbd0a252971be86d6579f0dfc87f8de5b9c47 web
- https://github.com/fastify/fast-uri/commit/52774a5c35df36b0bbe439cd4c12c3dc0e50e3b9 web
- https://github.com/fastify/fast-uri/commit/7c19f8b97ec51f1f20b4e3d9d5820cb8d5176058 web
- https://github.com/fastify/fast-uri/commit/9eb8759a9825c046f57f7f695f1944bc39b88abd web
- https://github.com/fastify/fast-uri/commit/acc5c5d60c4209571789496e1732468911c7e12a web
- https://github.com/fastify/fast-uri/commit/b110a3571c37dfcf9d1c72ce2e2e178c78d1a424 web
- https://cna.openjsf.org/security-advisories.html web
- https://github.com/fastify/fast-uri package
- https://github.com/fastify/fast-uri/releases/tag/v2.4.8 web
- https://github.com/fastify/fast-uri/releases/tag/v3.1.9 web
- https://github.com/fastify/fast-uri/releases/tag/v4.2.3 web