CVE-2026-86250 — h3 before 2.0.1-rc.18 Denial of Service via Unbounded Chunked Cookie
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 ca…
Published: 2026-09-06 · CVSS: 8.7 · CVSS 4.0
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7