netty netty-codec-mqtt up to 4.1.133.Final/4.2.13.Final Properties Section decodeVariableHeader resource consumption

CVSS Meta Temp Score
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CTI Interest Score
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6.0$0-$5k0.00

Summaryinfo

A vulnerability was found in netty netty-codec-mqtt up to 4.1.133.Final/4.2.13.Final. It has been declared as problematic. Impacted is the function decodeVariableHeader of the component Properties Section. Such manipulation leads to resource consumption. This vulnerability is listed as CVE-2026-44248. The attack may be performed from remote. There is no available exploit. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in netty netty-codec-mqtt up to 4.1.133.Final/4.2.13.Final. It has been rated as problematic. Affected by this issue is the function decodeVariableHeader of the component Properties Section. The manipulation with an unknown input leads to a resource consumption vulnerability. Using CWE to declare the problem leads to CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. Impacted is availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-44248 since 05/05/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1499 by the MITRE ATT&CK project.

The vulnerability scanner Nessus provides a plugin with the ID 321020 (SUSE SLED15 / SLES15 Security Update : netty, netty-tcnative (SUSE-SU-2026:2308-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 4.1.133.Final or 4.2.13.Final eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (321020). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.0
VulDB Meta Temp Score: 6.0

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔒

CNA Base Score: 5.3
CNA Vector (GitHub_M): 🔒

CVSSv2info

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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Resource consumption
CWE: CWE-400 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 321020
Nessus Name: SUSE SLED15 / SLES15 Security Update : netty, netty-tcnative (SUSE-SU-2026:2308-1)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: netty-codec-mqtt 4.1.133.Final/4.2.13.Final

Timelineinfo

05/05/2026 CVE reserved
05/13/2026 +8 days Advisory disclosed
05/13/2026 +0 days VulDB entry created
06/15/2026 +33 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-44248 (🔒)
GCVE (CVE): GCVE-0-2026-44248
GCVE (VulDB): GCVE-100-363698

Entryinfo

Created: 05/13/2026 21:02
Updated: 06/15/2026 04:35
Changes: 05/13/2026 21:02 (65), 05/19/2026 10:31 (11), 06/15/2026 04:35 (2)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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