PT-2026-60601 · H2O · Quicly

CVE-2026-44435 · Published 2026-07-16 · Updated 2026-07-16

NVD

CVSS v3.1

7.5

High

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Quicly is an IETF QUIC protocol implementation intended primarily for use within the H2O HTTP server. Prior to commit 937d0e9, an assertion failure is raised when the total number of valid handshake messages received over a CRYPTO stream of a single packet number space exceeds 32KB, causing a Denial of Service. This issue has been fixed by commit 937d0e9.

Fix

Resource Exhaustion

Assertion Failure

Weakness Enumeration

CWE-400

CWE-617

Related Identifiers

CVE-2026-44435

Affected Products

Quicly

References · 3

• https://nvd.nist.gov/vuln/detail/CVE-2026-44435 · Security Note
• https://github.com/h2o/quicly/security/advisories/GHSA-2cw9-5673-73gv · Note
• https://github.com/h2o/quicly/commit/937d0e9e7c669fc2bee4920632ab6aaac60e4d81 · Note