---
id: CVE-2026-56818
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, the RedisArrayAggregator Redis codec clears
  retained partial aggregate state when the maxNestedArrayDepth limit is
  exceeded, b…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L'
cwe:
  - CWE-401
  - CWE-703
  - CWE-772
vendor: netty
product: netty
affected:
  - netty < 4.1.136
  - 'netty >= 4.2.0, < 4.2.16'
patched:
  - netty 4.2.16
published: '2026-08-07'
updated: '2026-09-23'
sourceUpdated: '2026-09-23T15:56:16.860'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-56818'
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/pull/17065'
    label: security-advisories@github.com
  - url: 'https://github.com/netty/netty/security/advisories/GHSA-p9jm-q85p-7mcp'
    label: security-advisories@github.com
  - url: 'https://github.com/netty/netty/security/advisories/GHSA-p9jm-q85p-7mcp'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: 'https://github.com/advisories/GHSA-p9jm-q85p-7mcp'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-56818.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-56818'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2507476'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-56818'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-56818'
tags:
  - nvd
  - ghsa
  - maven
  - csaf
  - vex
  - red-hat
epss: 0.00473
epssPercentile: 0.38324
aliases:
  - GHSA-p9jm-q85p-7mcp
ecosystem: maven
ingestedAt: '2026-08-07T18:15:57.282Z'
scores:
  nvd: 6.5
  vendor: 7.5
---

## Overview

Netty is an asynchronous, event-driven network application framework. Prior to 4.1.136.Final and 4.2.16.Final, the RedisArrayAggregator Redis codec clears retained partial aggregate state when the maxNestedArrayDepth limit is exceeded, but it does not clear the same state when the sibling maxElements limit is exceeded. A peer can start a valid RESP array, send a bulk string child, then send a nested array header longer than the configured maxElements. Netty throws a decoder exception in decodeRedisArrayHeader, but the existing partial aggregate remains retained in the handler. If the application leaves the channel alive after the exception, later messages are still consumed into the pre-error aggregate, allowing an unauthenticated peer to keep attacker-controlled aggregate state alive across a security-limit exception and pin retained pooled buffers. 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`

## Package advisory (CVE-2026-56818)

Affected packages:

- `io.netty:netty-codec-redis < 4.1.136.Final`
- `io.netty:netty-codec-redis >= 4.2.0-Final, < 4.2.16.Final`

Patched in:

- `io.netty:netty-codec-redis 4.1.136.Final`
- `io.netty:netty-codec-redis 4.2.16.Final`

Source: https://github.com/advisories/GHSA-p9jm-q85p-7mcp

## Vendor advisories

- **Red Hat VEX** · Important · affected: Red Hat build of Apache Camel for Spring Boot 4, Red Hat Data Grid 8, Red Hat JBoss Enterprise Application Platform 7, Red Hat JBoss Enterprise Application Platform Expansion Pack, Red Hat Single Sign-On 7 · no fix planned: Red Hat JBoss Enterprise Application Platform 7, Red Hat Single Sign-On 7, Red Hat build of Apache Camel for Spring Boot 4, Red Hat Data Grid 8, … · updated 2026-09-23 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-56818.json)