Description
A flaw was found in Netty's MqttDecoder. An unauthenticated remote attacker can exploit this vulnerability by sending a specially crafted MQTT CONNECT packet. The decoder fails to properly validate the 'Properties Length' against the 'Remaining Length', allowing an attacker to bypass size limits. This leads to excessive memory and CPU consumption, resulting in a denial of service (DoS) due to an OutOfMemoryError.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Red Hat | Red Hat AMQ Broker 7 | — | — |
| Red Hat | Red Hat build of Apache Camel for Spring Boot 4 | — | — |
| Red Hat | Red Hat Fuse 7 | — | — |
| Red Hat | Red Hat JBoss Enterprise Application Platform 7 | — | — |
| Red Hat | Red Hat Single Sign-On 7 | — | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | netty | No fix yet | — |
| Debian 13 | netty | No fix yet | — |
| Debian 12 | netty | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | netty | No fix yet | — |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 26.04 LTS | netty | No fix yet | — |
| Ubuntu Pro 24.04 LTS | netty | No fix yet | — |
| Ubuntu Pro 22.04 LTS | netty | No fix yet | — |
| Ubuntu Pro 20.04 LTS | netty | No fix yet | — |
| Ubuntu Pro 18.04 LTS | netty | No fix yet | — |
| Ubuntu Pro 16.04 LTS | netty | No fix yet | — |
| Ubuntu Pro 14.04 LTS | netty | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | netty | 4.1.138-150200.4.56.1 | SUSE-SU-2026:4391-1 |
| SLES 15 SP7 | netty-tcnative | 2.0.84-150200.3.51.1 | SUSE-SU-2026:4391-1 |
| SLES 15 SP6 | netty-tcnative | 2.0.84-150200.3.51.1 | SUSE-SU-2026:4391-1 |
| SLES 15 SP5 | netty-tcnative | 2.0.84-150200.3.51.1 | SUSE-SU-2026:4391-1 |
| SLES 15 SP4 | netty-tcnative | 2.0.84-150200.3.51.1 | SUSE-SU-2026:4391-1 |
Show 5 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 15 SP6 | netty-tcnative | 2.0.84-150200.3.51.1 | SUSE-SU-2026:4391-1 |
| SLES for SAP 15 SP5 | netty-tcnative | 2.0.84-150200.3.51.1 | SUSE-SU-2026:4391-1 |
| SLES for SAP 15 SP4 | netty-tcnative | 2.0.84-150200.3.51.1 | SUSE-SU-2026:4391-1 |
| SLE HPC 15 SP5 | netty-tcnative | 2.0.84-150200.3.51.1 | SUSE-SU-2026:4391-1 |
| SLE HPC 15 SP4 | netty-tcnative | 2.0.84-150200.3.51.1 | SUSE-SU-2026:4391-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | netty | 4.1.138-1.1 | openSUSE-SU-2026:11882-1 |
Advisories 3
- WID-SEC-2026-3477 Netty: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 8, 2026
- SUSE-SU-2026:4391-1 Security update for netty, netty-tcnative SUSE / openSUSE Security Updates · Sep 30, 2026
- openSUSE-SU-2026:11882-1 netty-4.1.138-1.1 on GA media SUSE / openSUSE Security Updates · Sep 25, 2026
References
- https://access.redhat.com/security/cve/CVE-2026-93575 vdb-entry
- RHBZ#2536967 issue-tracking