CVE-2026-44248

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.

CVSS v3 5.3 MEDIUM

5.3^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 3.9 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact LOW

Scope UNCHANGED

References

Link	Resource
https://github.com/netty/netty/security/advisories/GHSA-jfg9-48mv-9qgx	Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:37390
https://access.redhat.com/errata/RHSA-2026:41951
https://access.redhat.com/errata/RHSA-2026:66488
https://access.redhat.com/errata/RHSA-2026:66545
https://access.redhat.com/security/cve/CVE-2026-44248
https://bugzilla.redhat.com/show_bug.cgi?id=2477231
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-44248.json

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:netty:netty::::::::
	cpe:2.3:a:netty:netty::::::::

History

No history.

Information

Published : 2026-05-13 19:17

Updated : 2026-09-11 13:18

NVD link : CVE-2026-44248

Mitre link : CVE-2026-44248

CVE.ORG link : CVE-2026-44248

JSON object : View

Products Affected

netty

netty

CWE

CWE-400

Uncontrolled Resource Consumption

CWE-770

Allocation of Resources Without Limits or Throttling

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