CVE-2026-86250

Summary

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.

Affected Software

VendorProductVersion RangeStatus
h3jsh32.0.0-beta.4 < 2.0.1-rc.18affected
h3jsh32.0.1-rc.18unaffected

Weaknesses

  • CWE-400: Uncontrolled Resource Consumption

References