---
id: CVE-2026-56817
title: >-
  io.netty/netty-codec-xml: Netty: Information disclosure via XML External
  Entity (XXE) vulnerability (CVE-2026-56817)
summary: >-
  A flaw was found in Netty, a network application framework. A remote attacker
  could exploit this vulnerability by sending specially crafted XML data
  containing a DOCTYPE declaration to a vulnerable XmlDecoder within the Netty
  channel pipel…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'
cvssSource: vendor
cwe: CWE-611
vendor: Red Hat
product: Red Hat JBoss Enterprise Application Platform 7
affected:
  - jboss_enterprise_application_platform 7
  - single_sign_on 7
  - data_grid 8.6.3
  - build_of_apache_camel_4_18_3_for_spring_boot 3.5.16
patched:
  - data_grid 8.6.3
  - build_of_apache_camel_4_18_3_for_spring_boot 3.5.16
published: '2026-07-21'
updated: '2026-09-21'
sourceUpdated: '2026-09-21T16:20:17+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-56817.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-56817.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-56817'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2505975'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-56817'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-56817'
  - url: >-
      https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b
  - url: >-
      https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6
  - url: 'https://github.com/netty/netty/releases/tag/netty-4.1.136.Final'
  - url: 'https://github.com/netty/netty/releases/tag/netty-4.2.16.Final'
  - url: 'https://github.com/netty/netty/security/advisories/GHSA-4qhr-g3c6-fcfx'
  - url: 'https://access.redhat.com/errata/RHSA-2026:69296'
  - url: 'https://access.redhat.com/errata/RHSA-2026:54622'
  - url: 'https://github.com/advisories/GHSA-4qhr-g3c6-fcfx'
tags:
  - csaf
  - vex
  - red-hat
  - ghsa
  - maven
epss: 0.00694
epssPercentile: 0.50919
aliases:
  - GHSA-4qhr-g3c6-fcfx
ecosystem: maven
ingestedAt: '2026-07-22T22:06:57.796Z'
---

## Overview

A flaw was found in Netty, a network application framework. A remote attacker could exploit this vulnerability by sending specially crafted XML data containing a DOCTYPE declaration to a vulnerable XmlDecoder within the Netty channel pipeline. This can lead to an XML External Entity (XXE) vulnerability, potentially allowing the attacker to disclose sensitive information from the system.

## Vendor advisories

- **RHSA-2026:69296** · Red Hat · fixed in: Red Hat Data Grid 8.6.3 · released 2026-09-21 · [advisory](https://access.redhat.com/errata/RHSA-2026:69296)
- **RHSA-2026:54622** · Red Hat · fixed in: Red Hat build of Apache Camel 4.18.3 for Spring Boot 3.5.16 · released 2026-08-13 · [advisory](https://access.redhat.com/errata/RHSA-2026:54622)
- **Red Hat VEX** · Important · affected: Red Hat JBoss Enterprise Application Platform 7, Red Hat Single Sign-On 7 · no fix planned: Red Hat JBoss Enterprise Application Platform 7, Red Hat Single Sign-On 7 · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-56817.json)

**io.netty/netty-codec-xml: Netty: Information disclosure via XML External Entity (XXE) vulnerability** — rated Important by Red Hat. Released 2026-07-21, updated 2026-09-21.

Affected:

- Red Hat JBoss Enterprise Application Platform 7
- Red Hat Single Sign-On 7

Fixed:

- Red Hat Data Grid 8.6.3
- Red Hat build of Apache Camel 4.18.3 for Spring Boot 3.5.16

No fix planned:

- Red Hat JBoss Enterprise Application Platform 7
- Red Hat Single Sign-On 7

Not affected:

- Red Hat JBoss Enterprise Application Platform Expansion Pack

## Remediation

Before applying this update, make sure all previously released errata relevant to your system have been applied.

For details on how to apply this update, refer to: https://access.redhat.com/articles/11258 https://access.redhat.com/errata/RHSA-2026:69296
Before applying this update, make sure all previously released errata
relevant to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258 https://access.redhat.com/errata/RHSA-2026:54622

Workarounds / mitigations:

- Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

## Package advisory (CVE-2026-56817)

Affected packages:

- `io.netty:netty-codec-xml >= 4.2.0.Final, <= 4.2.15.Final`
- `io.netty:netty-codec-xml >= 4.1.0.Final, <= 4.1.135.Final`

Patched in:

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

Source: https://github.com/advisories/GHSA-4qhr-g3c6-fcfx