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CVE-2026-86250

CVE-2026-86250 · h3 before 2.0.1-rc.18 Denial of Service via Unbounded Chunked Cookie

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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.

CVSS 8.7 · High · EPSS 0.5% · Fix available

Published
Updated

Stack: node

Affected products and versions

  • h3

    Versions
    • ≥ 2.0.0-beta.4, < 2.0.1-rc.18: Affected (semver)
    • 2.0.1-rc.18: Not affected (semver)

    Update to 2.0.1-rc.18

  • h3 npm

    Affected ranges
    • SEMVER: ≥ 2.0.0-beta.4, < 2.0.1-rc.18

    Update to 2.0.1-rc.18

Original sources

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