CVE-2026-44248

Fixed in a distro release EPSS <1%CVSS 5.3

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, the MQTT 5 header Properties section is parsed and buffered before any message size limit is applied. Specifically, in MqttDecoder, the decodeVariableHeader() method is called before the bytesRemainingBeforeVariableHeader > maxBytesInMessage check. The decodeVariableHeader() can call other methods which will call decodeProperties(). Effectively, Netty does not apply any limits to the size of the properties being decoded. Additionally, because MqttDecoder extends ReplayingDecoder, Netty will repeatedly re-parse the enormous Properties sections and buffer the bytes in memory, until the entire thing parses to completion. This can cause high resource usage in both CPU and memory. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

Published 2026-05-13 · CVE record · OSV

Products: netty, io.netty netty-codec-mqtt, Red Hat AMQ Broker 7.13.6, Red Hat AMQ Broker 7.14.1, Red Hat build of Apache Camel 4.18.1.P1 for Spring Boot 3.5.16, Red Hat Data Grid 8.6.2, Red Hat Fuse 7, Red Hat JBoss Enterprise Application Platform 7, Red Hat JBoss Enterprise Application Platform Expansion Pack, Red Hat Process Automation 7, Red Hat Single Sign-On 7

Fixed upstream

Distro releases