CVE-2026-86251
Last modified
CVE-2026-86251 is a medium-severity vulnerability rated 5.9/10 on the CVSS scale. h3 versions before 1.15.9 contain a path traversal vulnerability in the serveStatic utility. A double-decoding flaw allows a request path containing double-encoded dot sequences (e.g. EPSS estimates a 0.30% chance of exploitation in the next 30 days.
Description
h3 versions before 1.15.9 contain a path traversal vulnerability in the serveStatic utility. A double-decoding flaw allows a request path containing double-encoded dot sequences (e.g. %252e%252e) to be decoded to %2e%2e, which survives resolveDotSegments() because that function only checks for literal '.' characters. When the resulting asset ID is resolved by URL-based backends (CDN, S3, object storage), %2e%2e is interpreted as '..' per RFC 3986, enabling path traversal to read arbitrary files from the backend.
Metrics
Weakness Enumeration
Affected Software
Source: CNA advisory (CVE.org). NVD analysis pending.
| Vendor | Product | Versions |
|---|---|---|
| h3js | h3 | < 1.15.9 |
References
Timeline
- Published
- Last Modified
- Status
- Awaiting Analysis
Frequently Asked Questions
What is CVE-2026-86251?
How severe is CVE-2026-86251?
How do I fix CVE-2026-86251?
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
Related CVEs from 2026
- CVE-2026-86241A weakness has been identified in liufee FeehiCMS up to 2.1.…4.3
- CVE-2026-86242Bifrost HTTP transport before 2.0.0 accepts an enabled custo…8.1
- CVE-2026-86244A security vulnerability has been detected in FastAdmin up t…4.3
- CVE-2026-86245A vulnerability was detected in itsourcecode Sales and Inven…6.3
- CVE-2026-8625The Dear Flipbook – PDF Flipbook, 3D Flipbook, PDF embed, PD…6.4
- CVE-2026-86250h3 versions before 2.0.1-rc.18 fail to validate the chunk co…7.5
- CVE-2026-86252h3 versions before 1.15.9 fail to sanitize carriage return c…5.3
- CVE-2026-86253h3 (npm package) versions <= 2.0.1-rc.14 contain a path trav…5.9
- CVE-2026-86254wger versions through master contain an incomplete authoriza…6.8
- CVE-2026-86255wger before 2.5 fails to validate the maximum duration of ro…6.5
- CVE-2026-86256wger before 2.6 (affected versions <= 2.5.0) contains an ope…5.4
- CVE-2026-86257wger before 2.6 fails to sanitize first_name and last_name f…5.4
Are you affected by CVE-2026-86251?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST