CVE-2026-86250EPSS p39.8%

CVE-2026-86250CVE-2026-86250

Description

h3 versions before 2.0.1-rc.18 fail to validate the chunk count parsed from user-controlled cookie values in setChunkedCookie() and deleteChunkedCookie() functions. Attackers can send a crafted cookie header with an extremely large chunk count to trigger an O(n²) cleanup loop that hangs the server process.

Scoring

CVSS 7.5 ()
VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS0.49% probability of exploitation · percentile 39.8% · 2026-10-05T12:00:23Z
Last modified2026-09-18
Sourced from NVD + FIRST.org EPSS. Curated for EU compliance use cases by Adam Lundqvist, Founder at SQUR.