Bug 2505424 (CVE-2026-56816)

Summary:	CVE-2026-56816 io.netty:netty-codec-http3: Netty: Denial of Service due to uncontrolled memory buffering in HTTP/3
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	sdawley
Target Milestone:	---	Keywords:	Security
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Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in Netty. An unauthenticated remote attacker can exploit a vulnerability in Netty's `Http3FrameCodec` by sending specially crafted HTTP/3 reserved frames with excessive payload lengths. This can lead to uncontrolled memory buffering, causing memory exhaustion and a denial of service (DoS) for the affected system.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
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Description OSIDB Bzimport 2026-07-21 22:30:56 UTC

Netty is a network application framework for development of protocol servers and clients. Prior to 4.2.16.Final, Netty's `Http3FrameCodec` buffers incoming data for HTTP/3 reserved frame types up to the wire-specified payload length without limits; `decodeFrame` trusts `payLoadLength`, allowing an attacker to open multiple QUIC streams and send reserved frames with very large payload lengths to cause memory exhaustion and denial of service. This issue is fixed in version 4.2.16.Final.