h3 before 1.15.6 Path Traversal via Percent-Encoded Dot Segments

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-86253
StatePUBLISHED
AssignerVulnCheck
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-06 12:17:16 UTC
Updated2026-09-10 16:18:02 UTC
Descriptionh3 (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.

Risk And Classification

Primary CVSS: v4.0 8.2 HIGH from [email protected]

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.004290000 probability, percentile 0.362000000 (date 2026-09-10)

Problem Types: CWE-22 | CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary8.2HIGHCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/C...
4.0CNACVSS8.2HIGHCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
3.1[email protected]Secondary5.9MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
3.1CNACVSS5.9MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
High
Attack Requirements
Present
Privileges Required
None
User Interaction
None
Confidentiality
High
Integrity
None
Availability
None
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA H3js H3 affected 1.15.6 semver Not specified
CNA H3js H3 unaffected 1.15.6 semver Not specified
CNA H3js H3 affected 2.0.0-beta.0 2.0.1-rc.15 semver Not specified
CNA H3js H3 unaffected 2.0.1-rc.15 semver Not specified

References

ReferenceSourceLinkTags
www.vulncheck.com/advisories/h3-before-1.15.6-path-traversal-via-percent-encode... [email protected] www.vulncheck.com
github.com/h3js/h3/security/advisories/GHSA-wr4h-v87w-p3r7 [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: 0xkakash1 (en)

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