Netty: Resource exhaustion in MqttDecoder
Summary
| CVE | CVE-2026-44248 |
|---|---|
| State | PUBLISHED |
| Assigner | GitHub_M |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-05-13 19:17:27 UTC |
| Updated | 2026-07-21 12:18:40 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 7.5 HIGH from [email protected]
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS: 0.000180000 probability, percentile 0.049170000 (date 2026-05-25)
Problem Types: CWE-400 | CWE-770 | CWE-400 CWE-400: Uncontrolled Resource Consumption | CWE-770 Allocation of Resources Without Limits or Throttling
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | ADP | CVSS | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | [email protected] | Secondary | 5.3 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
| 3.1 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | Secondary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | CNA | DECLARED | 5.3 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
NoneAvailability
HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD Known Affected Configurations (CPE 2.3)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Netty | Netty | affected >= 4.2.0.Alpha1, < 4.2.13.Final | Not specified |
| CNA | Netty | Netty | affected < 4.1.133.Final | Not specified |
| CNA | Io.netty | Netty-codec-mqtt | affected >= 4.2.0.Alpha1, < 4.2.13.Final | Not specified |
| CNA | Io.netty | Netty-codec-mqtt | affected < 4.1.133.Final | Not specified |
| ADP | Red Hat | Red Hat Build Of Apache Camel 4.18.1.P1 For Spring Boot 3.5.16 | unaffected codec-mqtt * rpm | Not specified |
| ADP | Red Hat | Red Hat Data Grid 8.6.2 | unaffected codec-mqtt * rpm | Not specified |
| ADP | Red Hat | Red Hat AMQ Broker 7 | Not specified | Not specified |
| ADP | Red Hat | Red Hat Fuse 7 | Not specified | Not specified |
| ADP | Red Hat | Red Hat JBoss Enterprise Application Platform 7 | Not specified | Not specified |
| ADP | Red Hat | Red Hat JBoss Enterprise Application Platform Expansion Pack | Not specified | Not specified |
| ADP | Red Hat | Red Hat Process Automation 7 | Not specified | Not specified |
| ADP | Red Hat | Red Hat Single Sign-On 7 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-44248.json | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | security.access.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-44248 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:37390 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:41951 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| github.com/netty/netty/security/advisories/GHSA-jfg9-48mv-9qgx | [email protected] | github.com | Vendor Advisory |
| bugzilla.redhat.com/show_bug.cgi | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | bugzilla.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| ADP | 2026-05-13T19:02:22.095Z | Reported to Red Hat. |
| ADP | 2026-05-13T18:23:37.563Z | Made public. |
Solutions
ADP: RHSA-2026:41951: Red Hat Data Grid 8.6.2
ADP: RHSA-2026:37390: Red Hat build of Apache Camel 4.18.1.P1 for Spring Boot 3.5.16
There are currently no legacy QID mappings associated with this CVE.