CVE-2026-86250
HIGH
NVD
CVSS Score
7.5
Severity
HIGH
Published
Sep 06, 2026
Vendor
unknown
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.