VULNERABILITY INTELLIGENCE

CVE-2026-86253

CVSS score5.9 MEDIUM
EPSS probability0.62%
CISA KEVNot currently listed
Published2026-09-06
Last modified2026-09-10
CVSS vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Description

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.

Weakness classification

  • disclosure@vulncheck.com: CWE-22

Primary references