CVE-2026-44248
Full vulnerability record from the local CVENow database.
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.
Severity
HIGH
CVSS score
7.5
(v3.1)
Vulnerability status
Modified
Source identifier
Published
2026-05-13 19:17:27.143000
Last modified
2026-10-26 17:10:03.270000
View original CVE JSON
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"sourceIdentifier": "[email protected]",
"published": "2026-05-13T19:17:27.143",
"lastModified": "2026-10-26T17:10:03.270",
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"value": "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."
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"value": "Netty es un framework de aplicación de red asíncrono y basado en eventos. Antes de 4.2.13.Final y 4.1.133.Final, la sección de Propiedades del encabezado MQTT 5 se analiza y almacena en búfer antes de que se aplique cualquier límite de tamaño de mensaje. Específicamente, en MqttDecoder, el método decodeVariableHeader() se llama antes de la comprobación bytesRemainingBeforeVariableHeader > maxBytesInMessage. El decodeVariableHeader() puede llamar a otros métodos que llamarán a decodeProperties(). Efectivamente, Netty no aplica ningún límite al tamaño de las propiedades que se están decodificando. Además, debido a que MqttDecoder extiende ReplayingDecoder, Netty volverá a analizar repetidamente las enormes secciones de Propiedades y almacenará los bytes en la memoria, hasta que todo se analice por completo. Esto puede causar un alto uso de recursos tanto en la CPU como en la memoria. Esta vulnerabilidad se corrige en 4.2.13.Final y 4.1.133.Final."
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