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.
Published: 2026-09-06
Score: 5.3 Medium
EPSS: < 1% Very Low
KEV: No
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

No vendor fix or workaround currently provided.

Additional remediation guidance may be available on OpenCVE Cloud.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

History

Tue, 08 Sep 2026 14:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Sun, 06 Sep 2026 13:45:00 +0000

Type Values Removed Values Added
First Time appeared H3js
H3js h3
Vendors & Products H3js
H3js h3

Sun, 06 Sep 2026 12:15:00 +0000

Type Values Removed Values Added
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.
Title h3 before 2.0.1-rc.18 Open Redirect via redirectBack()
Weaknesses CWE-601
References
Metrics cvssV3_1

{'score': 5.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N'}

cvssV4_0

{'score': 5.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-09-08T13:28:55.791Z

Reserved: 2026-09-05T11:52:36.822Z

Link: CVE-2026-86205

cve-icon Vulnrichment

Updated: 2026-09-08T13:28:23.543Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-09-06T12:17:15.277

Modified: 2026-09-08T20:00:18.870

Link: CVE-2026-86205

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-06T13:30:07Z

Weaknesses