CVE-2026-110095: fast-uri Improper Resolution of Path Equivalence

Vulnerability summary

CVE-2026-110095 is a low (CVSS 3.7) Improper Resolution of Path Equivalence vulnerability in fast-uri. EPSS estimates a 0.23% chance of exploitation in the next 30 days, higher than 13.1% of scored vulnerabilities.

Timeline

1. 20-10-2026
   PublishedVulnerability first disclosed.
2. 20-10-2026
   Last modifiedVulnerability information updated.

Description

fast-uri is a dependency-free RFC 3986 URI parser and serializer for Node.js. In versions before 2.4.8, from 3.0.0 through 3.1.8, and from 4.0.0 through 4.2.2, the normalize() and serialize() functions apply RFC 3986 dot-segment removal to the path of a relative-path reference, even though that algorithm is defined only for the merged target path during resolution, so a leading parent-directory segment can be dropped and a document-relative reference can become root-relative. An application that normalizes an attacker-supplied or user-supplied relative reference and then resolves it, or uses it as a cache, deduplication, or authorization key, can have the reference escape its intended directory and point at a different resource. The issue is fixed in fast-uri 2.4.8, 3.1.9, and 4.2.3, and users should upgrade to one of these versions or later. As a workaround, resolve a relative reference against its absolute base first and normalize the absolute result instead of normalizing the reference beforehand.

• CWE-41Improper Resolution of Path EquivalenceThe product is vulnerable to file system contents disclosure through path equivalence. Path equivalence involves the use of special characters in file and directory names. The associated manipulations are intended to generate multiple names for the same object.