cve.bz

CVE-2026-86205

5.3 mediumEPSS 0.3%

Medium (5.3). EPSS 0.3% chance of exploitation in the next 30 days. Fixed in h3 2.0.1-rc.18.

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

CVSS 4.0

5.3 medium
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

CVSS 3.1

5.4 medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
EPSS
0.3% chance of exploitation in the next 30 days; higher than 19% of CVEs (scores of 2026-10-31)
CWE
CWE-601
Published
Modified
Record from
the NVD, synced

Packages (OSV)

AdvisoryEcosystemPackageAffectedFixed in
GHSA-fp4x-ggrf-wmc6npmh3>=2.0.1-rc.17 <2.0.1-rc.182.0.1-rc.18

References

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