---
id: CVE-2026-73507
title: 'Netty is an asynchronous, event-driven network application framework'
summary: >-
  Netty is an asynchronous, event-driven network application framework. Prior to
  4.1.136.Final and 4.2.16.Final,
  io.netty.handler.codec.xml.XmlFrameDecoder.decode() failed to preserve
  closing-tag parser state across invocations, so an unau…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-400
  - CWE-835
vendor: netty
product: netty
affected:
  - netty < 4.1.136
  - 'netty >= 4.2.0, < 4.2.16'
patched:
  - netty 4.2.16
published: '2026-08-13'
updated: '2026-09-23'
sourceUpdated: '2026-09-23T15:40:24.057'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73507'
references:
  - url: >-
      https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b
    label: security-advisories@github.com
  - url: >-
      https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6
    label: security-advisories@github.com
  - url: 'https://github.com/netty/netty/releases/tag/netty-4.1.136.Final'
    label: security-advisories@github.com
  - url: 'https://github.com/netty/netty/releases/tag/netty-4.2.16.Final'
    label: security-advisories@github.com
  - url: 'https://github.com/netty/netty/security/advisories/GHSA-v74w-7mr3-4qg3'
    label: security-advisories@github.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-73507.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-73507'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2515374'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-73507'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73507'
  - url: 'https://access.redhat.com/errata/RHSA-2026:71675'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
epss: 0.00793
epssPercentile: 0.54423
ingestedAt: '2026-09-09T21:22:45.533Z'
---

## Overview

Netty is an asynchronous, event-driven network application framework. Prior to 4.1.136.Final and 4.2.16.Final, io.netty.handler.codec.xml.XmlFrameDecoder.decode() failed to preserve closing-tag parser state across invocations, so an unauthenticated remote attacker could trickle-feed repeated </ sequences that repeatedly rescanned the accumulated buffer and exhausted an EventLoop thread's CPU, causing denial of service with a maxFrameLength of 1 MB. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

## Affected

- `netty < 4.1.136`
- `netty >= 4.2.0, < 4.2.16`

## Remediation

Upgrade past the affected range:

- `netty 4.2.16`

## Vendor advisories

- **RHSA-2026:71675** · Red Hat · fixed in: Red Hat build of Apache Camel 4.18.4 for Spring Boot 3.5.16 · released 2026-09-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:71675)
- **Red Hat VEX** · Important · affected: Red Hat Single Sign-On 7 · no fix planned: Red Hat Single Sign-On 7 · updated 2026-09-24 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-73507.json)