CVE-2026-86253
h3 before 1.15.6 Path Traversal via Percent-Encoded Dot Segments
- State
- Published
- Severity
- 8.2 High
- Published
- Sep 6, 2026
- Updated
- Sep 10, 2026
- Reserved
- Sep 6, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.2 High | CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 5.9 Medium | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N | VulnCheck |
Weaknesses
- CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Affected Products
| Product | Versions |
|---|---|
h3h3js |
|
References
- GitHub Security Advisory (GHSA-wr4h-v87w-p3r7)vendor-advisory
- VulnCheck Advisory: h3 before 1.15.6 Path Traversal via Percent-Encoded Dot Segmentsthird-party-advisory
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