CVE-2026-86205
h3 before 2.0.1-rc.18 Open Redirect via redirectBack()
CVSS Score
5.4
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-601 |
| Vendor | h3js |
| Product | h3 |
| Published | Sep 6, 2026 |
| Last Updated | Sep 8, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None
Affected Versions
h3js / h3
2.0.1-rc.17 < 2.0.1-rc.18
References
Credits
🔍 offset