CVE-2026-110095

fast-uri vulnerable to improper path equivalence in relative reference normalization

Workarounds

Do not normalize a relative reference before resolving it. Resolve it against the absolute base first, then normalize the absolute result.

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.

CVE-2026-110095 has a CVSS score of 3.7 (Low). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.4.8, 3.1.9, 4.2.3); upgrading removes the vulnerable code path.

Kodem intelligence

Already deployed Kodem?

Upgrade to fast-uri 2.4.8, 3.1.9, or 4.2.3.

1. What is CVE-2026-110095? CVE-2026-110095 is a low-severity security vulnerability in fast-uri (npm), affecting versions < 2.4.8. It is fixed in 2.4.8, 3.1.9, 4.2.3.
2. How severe is CVE-2026-110095? CVE-2026-110095 has a CVSS score of 3.7 (Low). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of fast-uri are affected by CVE-2026-110095? fast-uri (npm) versions < 2.4.8 is affected.
4. Is there a fix for CVE-2026-110095? Yes. CVE-2026-110095 is fixed in 2.4.8, 3.1.9, 4.2.3. Upgrade to this version or later.
5. Is CVE-2026-110095 exploitable, and should I be worried? Whether CVE-2026-110095 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-110095 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-110095?
   • Upgrade fast-uri to 2.4.8 or later
   • Upgrade fast-uri to 3.1.9 or later
   • Upgrade fast-uri to 4.2.3 or later

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