CVE-2026-44435

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.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/h2o/quicly/commit/937d0e9e7c669fc2bee4920632ab6aaac60e4d81	Patch
https://github.com/h2o/quicly/security/advisories/GHSA-2cw9-5673-73gv	Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:h2o:quicly:*:*:*:*:*:*:*:*

History

24 Oct 2026, 20:10

Type	Values Removed	Values Added
Summary		(es) Quicly es una implementación del protocolo QUIC de la IETF destinada principalmente para su uso dentro del servidor HTTP H2O. Antes del commit 937d0e9, se produce un fallo de aserción cuando el número total de mensajes de handshake válidos recibidos a través de un flujo CRYPTO de un único espacio de número de paquete excede los 32KB, causando una denegación de servicio. Este problema ha sido solucionado por el commit 937d0e9.

Information

Published : 2026-07-16 23:16

Updated : 2026-10-24 20:10

NVD link : CVE-2026-44435

Mitre link : CVE-2026-44435

CVE.ORG link : CVE-2026-44435

JSON object : View

Products Affected

h2o

quicly

CWE

CWE-400

Uncontrolled Resource Consumption

CWE-617

Reachable Assertion

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