---
id: CVE-2026-86253
title: >-
  h3 (npm package) versions <= 2.0.1-rc.14 contain a path traversal
  vulnerability in serveStatic()
summary: >-
  h3 (npm package) versions <= 2.0.1-rc.14 contain a path traversal
  vulnerability in serveStatic(). On Node.js deployments, event.url.pathname is
  not normalized, so percent-encoded dot segments (%2e%2e) are passed to
  decodeURI() and decode…
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N'
cwe:
  - CWE-22
vendor: h3js
product: h3
affected:
  - h3 < 1.15.6
  - h3 >= 2.0.0-beta.0 < 2.0.1-rc.15
published: '2026-09-06'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T16:18:02.287'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-86253'
references:
  - url: 'https://github.com/h3js/h3/security/advisories/GHSA-wr4h-v87w-p3r7'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/h3-before-1.15.6-path-traversal-via-percent-encoded-dot-segments
    label: disclosure@vulncheck.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-86253.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-86253'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2529156'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-86253'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-86253'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-10T14:19:05.242837Z'
epss: 0.00429
epssPercentile: 0.36789
ingestedAt: '2026-09-07T04:04:50.629Z'
---

## Overview

h3 (npm package) versions <= 2.0.1-rc.14 contain a path traversal vulnerability in serveStatic(). On Node.js deployments, event.url.pathname is not normalized, so percent-encoded dot segments (%2e%2e) are passed to decodeURI() and decoded to ../ sequences without sanitization. An unauthenticated remote attacker can send crafted requests to endpoints served by serveStatic() to read arbitrary files outside the intended static directory. Fixed in 1.15.6 and 2.0.1-rc.15.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat OpenShift AI (RHOAI) · no fix planned: Red Hat OpenShift AI (RHOAI) · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-86253.json)