CVE-2026-93575 Io.netty/netty-codec-mqtt: netty: resource exhaustion in mqttdecoder
An unauthenticated remote attacker can cause denial of service in applications using Netty's MQTT decoder by sending a crafted CONNECT packet that bypasses size limits.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-93575?
CVE-2026-93575 is a high-severity denial of service vulnerability in Red Hat AMQ Broker 7, published on 18 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-1035
Which versions are affected by CVE-2026-93575?
How do I fix CVE-2026-93575?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-93575 being exploited?
There is no known exploitation of CVE-2026-93575 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-93575, GHSA-fcr3-v77c-x7hx, UBUNTU-CVE-2026-93575.