CVE-2026-86205h3 before 2.0.1-rc.18 Open Redirect via redirectBack()
Updated under an hour ago ()
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It affects h3js h3. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 5.4 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
- Weakness (CWE)
- CWE-601
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- VulnCheck
- NVD analysis
- Awaiting Analysis
- Record last updated
- Sep 8, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
h3js h3 h3js:h3 (from the name) | from 2.0.1-rc.17 before 2.0.1-rc.18; 2.0.1-rc.18 not affected | CNA record |
References
- https://github.com/h3js/h3/security/advisories/GHSA-fp4x-ggrf-wmc6vendor-advisory
- https://www.vulncheck.com/advisories/h3-before-2.0.1-rc.18-open-redirect-via-redirectbackthird-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.