CVE-2026-44248
Netty: Resource exhaustion in MqttDecoder
At a glance
- Source
- NVD
- EPSS
- EPSS 0.56 % · percentile 47 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Modified
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.
Weaknesses (CWE)
- CWE-400 — Uncontrolled Resource Consumption (DoS)
- CWE-770 — Allocation of Resources Without Limits or Throttling
References
- https://github.com/netty/netty/security/advisories/GHSA-jfg9-48mv-9qgx
- 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
- https://access.redhat.com/errata/RHSA-2026:66545
- https://access.redhat.com/errata/RHSA-2026:66488
- https://access.redhat.com/errata/RHSA-2026:41951
- https://access.redhat.com/errata/RHSA-2026:37390
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L | GitHub_M |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | redhat-SADP |
| CVSS 3.1 | MEDIUM 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L | NVD · security-advisories@github.com (Secondary) |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD · nvd@nist.gov (Primary) |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c (Secondary) |
Advisories
- GHSA-jfg9-48mv-9qgx — Netty MQTT: Resource exhaustion in MqttDecoder
European references
- ENISA EUVD · EUVD-2026-30132
- GCVE · GCVE-0-2026-44248
CERT-FR advisories
- CERTFR-2026-AVI-1385 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1206 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1165 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1067 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*< 4.1.133cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*≥ 4.2.0 < 4.2.13
Affected products
| Product | Versions |
|---|---|
| netty · netty | affected >= 4.2.0.Alpha1, < 4.2.13.Final ; affected < 4.1.133.Final |
| io.netty · netty-codec-mqtt | affected >= 4.2.0.Alpha1, < 4.2.13.Final ; affected < 4.1.133.Final |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |