---
id: CVE-2026-76816
title: 'Netty is an asynchronous, event-driven network application framework'
summary: >-
  Netty is an asynchronous, event-driven network application framework. Prior to
  versions 4.1.137.Final and 4.2.17.Final, MqttEncoder does not validate client
  identifiers, will topics, usernames, and PUBLISH topic names before encoding,
  al…
severity: low
cvss: 3.5
cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N'
cwe:
  - CWE-20
  - CWE-626
  - CWE-170
published: '2026-08-24'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T21:06:39.057'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-76816'
references:
  - url: >-
      https://github.com/netty/netty/commit/1b5abc6443b63726c72cdd285af2feb7ddbb8ff7
    label: security-advisories@github.com
  - url: >-
      https://github.com/netty/netty/commit/9e0519239108a69b7e9bbc5e9182ee139a0d7961
    label: security-advisories@github.com
  - url: 'https://github.com/netty/netty/security/advisories/GHSA-43fm-7cxg-hf3j'
    label: security-advisories@github.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-76816.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-76816'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2523094'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-76816'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-76816'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
epss: 0.00272
epssPercentile: 0.17421
ingestedAt: '2026-09-09T21:22:45.549Z'
vendor: Red Hat
product: Red Hat JBoss Enterprise Application Platform 7
affected:
  - amq_broker 7
  - build_of_apache_camel_for_spring_boot 4
  - fuse 7
  - jboss_enterprise_application_platform 7
  - single_sign_on 7
---

## Overview

Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.137.Final and 4.2.17.Final, MqttEncoder does not validate client identifiers, will topics, usernames, and PUBLISH topic names before encoding, allowing prohibited null bytes in MQTT UTF-8 string fields and potentially causing routing, access-control, or identity mismatches in downstream brokers. The vulnerability is exploitable when an application uses Netty's MQTT encoder to construct messages from user-controlled input. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Low · affected: Red Hat AMQ Broker 7, Red Hat build of Apache Camel for Spring Boot 4, Red Hat Fuse 7, Red Hat JBoss Enterprise Application Platform 7, Red Hat Single Sign-On 7 · no fix planned: Red Hat Fuse 7, Red Hat JBoss Enterprise Application Platform 7, Red Hat Single Sign-On 7, Red Hat AMQ Broker 7, … · updated 2026-09-23 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-76816.json)