HIGH 8.7 NVD
CVE-2026-86250
h3 versions before 2.0.1-rc.18 fail to validate the chunk count parsed from user-controlled cookie values in setChunkedCookie() and deleteChunkedCookie() functi
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.
References
- https://github.com/h3js/h3/security/advisories/GHSA-q5pr-72pq-83v3
- https://www.vulncheck.com/advisories/h3-before-2.0.1-rc.18-denial-of-service-via-unbounded
This high severity vulnerability with a CVSS score of 8.7 was published on 2026-09-06 via NVD.
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