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5.3 Medium

CVE-2026-44248 Netty is an asynchronous, event-driven network application framework

Description

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.

Affected products and versions

Product Affected versions Fixed in
netty 4.2 4.2.0.Alpha1 → < 4.2.13.Final 4.2.13.Final
netty 4.1 earliest → < 4.1.133.Final 4.1.133.Final
netty-codec-mqtt 4.2 4.2.0.Alpha1 → < 4.2.13.Final 4.2.13.Final
netty-codec-mqtt 4.1 earliest → < 4.1.133.Final 4.1.133.Final
Red Hat AMQ Broker 7 Versions not published
Red Hat build of Apache Camel for Spring Boot 4 Versions not published
Red Hat Data Grid 8 Versions not published
Red Hat Fuse 7 Versions not published
Red Hat Process Automation 7 Versions not published
Show the 7 other branches
Product Affected versions Fixed in
Red Hat JBoss Enterprise Application Platform 7 Versions not published
Red Hat JBoss Enterprise Application Platform Expansion Pack Versions not published
Red Hat Single Sign-On 7 Versions not published
Red Hat build of Apache Camel 4.18.1.P1 for Spring Boot 3.5.16 Versions not published
Red Hat Data Grid 8.6.2 Versions not published
Red Hat AMQ Broker 7.13.6 Versions not published
Red Hat AMQ Broker 7.14.1 Versions not published

References

Timeline

  1. Published
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Other CVEs of netty

The 95 CVEs of netty →
CVE-2026-100666 Netty's HttpServerCodec (io.netty:netty-codec-http) in versions 4.2.0.Final through 4.2.16.Final and in versions up to… 6.9 Medium CVE-2026-100665 Netty versions from 4.2.11.Final before 4.2.18.Final contain an incomplete hostname verification fix in the QUIC… 8.7 High CVE-2026-100664 Netty's HTTP/3 codec (io.netty:netty-codec-http3) versions 4.2.2.Final through 4.2.17.Final builds the HTTP/3 :authority… 8.7 High CVE-2026-100663 Netty's HTTP/3 codec (io.netty:netty-codec-http3) from 4.2.2.Final through 4.2.17.Final does not special-case HTTP/1… 8.7 High
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