Buffer Overflow Vulnerability in Netty MQTT 5 Framework
CVE-2026-44248

5.3MEDIUM

Key Information:

Vendor

Netty

Status
Netty
Netty-codec-MQtt
Vendor
CVE Published:
13 May 2026

What is CVE-2026-44248?

Netty, an asynchronous event-driven network application framework, contains a vulnerability in its MQTT 5 implementation where the Properties section of the header is parsed and buffered without applying any size limits. This oversight in the decodeVariableHeader() method allows for potential abuse, leading to high CPU and memory usage as large property sections are repeatedly parsed and buffered. This vulnerability is addressed in versions 4.2.13.Final and 4.1.133.Final, emphasizing the need for users to update to these versions to mitigate the risk of resource exhaustion.

Affected Version(s)

netty >= 4.2.0.Alpha1, < 4.2.13.Final < 4.2.0.Alpha1, 4.2.13.Final

netty < 4.1.133.Final < 4.1.133.Final

netty-codec-mqtt >= 4.2.0.Alpha1, < 4.2.13.Final < 4.2.0.Alpha1, 4.2.13.Final

References

https://github.com/netty/netty/security/advisories/GHSA-j...
x_refsource_CONFIRM

CVSS V3.1

Score:
5.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.