Remote service crash via oversized MQTT properties
Published Sep 18, 2026 · Updated Sep 18, 2026
Resource exhaustion in Netty netty-codec-mqtt allows remote attackers to crash MQTT 5 services with a crafted CONNECT packet. MqttDecoder.decodeProperties trusts an unbounded Properties Length without comparing it with Remaining Length, so ReplayingDecoder buffers the declared body and parses millions of attacker-supplied UserProperty objects. Unauthenticated network access to an application that processes MQTT 5 traffic through this decoder is required, and exploitation can exhaust CPU and memory until an OutOfMemoryError interrupts the service.
Summary
What happened
Resource exhaustion in Netty netty-codec-mqtt allows remote attackers to crash MQTT 5 services with a crafted CONNECT packet. MqttDecoder.decodeProperties trusts an unbounded Properties Length without comparing it with Remaining Length, so ReplayingDecoder buffers the declared body and parses millions of attacker-supplied UserProperty objects. Unauthenticated network access to an application that processes MQTT 5 traffic through this decoder is required, and exploitation can exhaust CPU and memory until an OutOfMemoryError interrupts the service.
The record
- CVE
- CVE-2026-93575
- Published
- Sep 18, 2026
- Updated
- Sep 18, 2026
- Vendor
- Commonhaus Foundation
- Product
- Red Hat JBoss Enterprise Application Platform 7
- Classifications
- CWE-400, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 18, 2026CVE publishedPublication date reported by the CVE source.
- Sep 18, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
- EmbeddedChannel MqttDecoder proof of conceptproof of concept · unverified
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Get started to see how Hinoki identifies affected software and validates exploitability in your environment.
Get started