CVE-2026-86205 (GCVE-0-2026-86205)
Vulnerability from cvelistv5 – Published: 2026-09-06 12:00 – Updated: 2026-09-08 13:28
VLAI
EPSS
VEX
Title
h3 before 2.0.1-rc.18 Open Redirect via redirectBack()
Summary
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.
Severity
5.4 (Medium)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-08 13:28 UTC
CWE
- CWE-601 - URL Redirection to Untrusted Site ('Open Redirect')
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/h3js/h3/security/advisories/GH… | vendor-advisory |
| https://www.vulncheck.com/advisories/h3-before-2.… | third-party-advisory |
Impacted products
Date Public
2026-03-21 00:00
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