CVE-2026-86205EPSS p17.6%

CVE-2026-86205CVE-2026-86205

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.

Scoring

CVSS 5.4 ()
VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
EPSS0.27% probability of exploitation · percentile 17.6% · 2026-10-05T12:00:23Z
Last modified2026-09-08
Sourced from NVD + FIRST.org EPSS. Curated for EU compliance use cases by Adam Lundqvist, Founder at SQUR.