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VULNERABILITIES

CVE-2026-86205 Details

Description

h3 versions before 2.0.1-rc.18 contain an open redirect vulnerability in the redirectBack() utility that fails to sanitize protocol-relative paths in the Referer header pathname. Attackers can craft a same-origin URL with a double-slash path segment that passes origin validation but produces a Location header interpreted by browsers as a protocol-relative redirect to an external domain.

Metrics

CVSS 3.x Severity and Vector Strings:

CNA: [email protected]CVSS-B:5.4 MEDIUMVector:CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

References to Advisories, Solutions, and Tools

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URLSource(s)Tag(s)
https://github.com/h3js/h3/security/advisories/GHSA-fp4x-ggrf-wmc6 CISA-ADP
https://github.com/h3js/h3/security/advisories/GHSA-fp4x-ggrf-wmc6 [email protected]
https://www.vulncheck.com/advisories/h3-before-2.0.1-rc.18-open-redirect-via-redirectback [email protected]

Weakness Enumeration

CWE-IDCWE NameSource
CWE-601URL Redirection to Untrusted Site ('Open Redirect')[email protected]

Affected Products

No affected product data is available for this CVE.

Change History

2 change records found show changes

QUICK INFO

CVE Dictionary Entry:
CVE-2026-86205
NVD Published Date:
Sep 6, 2026
NVD Last Modified:
Sep 8, 2026
Source:
[email protected]
CVE-2026-86205 Details - Not Deferred