Resource exhaustion in Netty - CVE-2026-44248

Vulnerability identifier: #VU130204

CSH Severity: Medium

CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-44248

CWE-ID: CWE-400

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to uncontrolled resource consumption in MqttDecoder when parsing MQTT 5 header Properties sections. A remote attacker can send a specially crafted MQTT message with an enormous Properties section to cause a denial of service.

The issue can lead to high CPU and memory usage because the Properties section is parsed and buffered before message size limits are applied, and repeated re-parsing occurs due to ReplayingDecoder behavior.

Netty
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Real Time 15
Development Tools Module
SUSE Package Hub 15
netty-tcnative-debugsource
netty-tcnative
netty
netty-javadoc

Install security update from vendor's website.

Netty - addressed in versions 4.1.133, 4.2.13
netty-tcnative-debugsource - update to 2.0.77-150200.3.39.1
netty-tcnative - update to 2.0.77-150200.3.39.1
netty - update to 4.1.133-150200.4.46.1
netty-javadoc - update to 4.1.133-150200.4.46.1

• https://github.com/netty/netty/security/advisories/GHSA-jfg9-48mv-9qgx

• Multiple vulnerabilities in Netty
• SUSE update for netty, netty-tcnative