---
id: CVE-2026-110095
aliases:
  - GHSA-xhq7-xmqj-769h
title: >-
  fast-uri vulnerable to improper path equivalence in relative reference
  normalization
summary: >-
  fast-uri vulnerable to improper path equivalence in relative reference
  normalization
severity: low
cvss: 3.7
cwe:
  - CWE-41
  - CWE-22
vendor: fast-uri
product: fast-uri
ecosystem: npm
affected:
  - fast-uri < 2.4.8
  - 'fast-uri >= 3.0.0, < 3.1.9'
  - 'fast-uri >= 4.0.0, < 4.2.3'
patched:
  - fast-uri 2.4.8
  - fast-uri 3.1.9
  - fast-uri 4.2.3
published: '2026-10-23'
updated: '2026-10-23'
sourceUpdated: '2026-10-23T21:39:38Z'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-xhq7-xmqj-769h'
references:
  - url: >-
      https://github.com/fastify/fast-uri/security/advisories/GHSA-xhq7-xmqj-769h
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-110095'
  - url: >-
      https://github.com/fastify/fast-uri/commit/048bbd0a252971be86d6579f0dfc87f8de5b9c47
  - url: >-
      https://github.com/fastify/fast-uri/commit/52774a5c35df36b0bbe439cd4c12c3dc0e50e3b9
  - url: >-
      https://github.com/fastify/fast-uri/commit/7c19f8b97ec51f1f20b4e3d9d5820cb8d5176058
  - url: >-
      https://github.com/fastify/fast-uri/commit/9eb8759a9825c046f57f7f695f1944bc39b88abd
  - url: >-
      https://github.com/fastify/fast-uri/commit/acc5c5d60c4209571789496e1732468911c7e12a
  - url: >-
      https://github.com/fastify/fast-uri/commit/b110a3571c37dfcf9d1c72ce2e2e178c78d1a424
  - url: 'https://cna.openjsf.org/security-advisories.html'
  - url: 'https://github.com/fastify/fast-uri/releases/tag/v2.4.8'
  - url: 'https://github.com/fastify/fast-uri/releases/tag/v3.1.9'
  - url: 'https://github.com/fastify/fast-uri/releases/tag/v4.2.3'
  - url: 'https://github.com/advisories/GHSA-xhq7-xmqj-769h'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-110095.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-110095'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2556002'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-110095'
tags:
  - ghsa
  - npm
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00289
epssPercentile: 0.21382
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-20T16:07:32.689199Z'
ingestedAt: '2026-10-20T07:55:43.639Z'
---

## Overview

### 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.

## Affected packages

- `fast-uri < 2.4.8`
- `fast-uri >= 3.0.0, < 3.1.9`
- `fast-uri >= 4.0.0, < 4.2.3`

## Remediation

Upgrade to a patched release:

- `fast-uri 2.4.8`
- `fast-uri 3.1.9`
- `fast-uri 4.2.3`

## Vendor advisories

- **Red Hat VEX** · Low · affected: Cost Management On Premise, Cryostat 4, Migration Toolkit for Applications 8, Multicluster Engine for Kubernetes, Network Observability Operator, OpenShift Lightspeed, … · no fix planned: Red Hat Ansible Automation Platform 2, Red Hat Directory Server 11, Red Hat Directory Server 12, Red Hat Openshift Data Foundation 4, … · updated 2026-10-20 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-110095.json)