CVE Vulnerabilities

CVE-2026-56817

Improper Restriction of XML External Entity Reference

Published: Jul 21, 2026 | Modified: Jul 30, 2026
CVSS 3.x
9.8
CRITICAL
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
RedHat/V2
RedHat/V3
7.5 IMPORTANT
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Ubuntu
MEDIUM
root.io logo minimus.io logo echo.ai logo

Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final through 4.2.15.Final and 4.1.0.Final through 4.1.135.Final, any caller that can deliver bytes to a Netty channel pipeline containing XmlDecoder can send XML with a DOCTYPE declaration to an AsyncXMLInputFactory instantiated with no security configuration, leaving DTD and entity handling active depending on Aalto XML async parser behavior and creating conditional XML external entity risk. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

Weakness

The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.

Affected Software

NameVendorStart VersionEnd Version
NettyNetty4.1.0 (including)4.1.136 (excluding)
NettyNetty4.2.0 (including)4.2.16 (excluding)
Red Hat build of Apache Camel 4.18.3 for Spring Boot 3.5.16RedHatnetty-codec-xml*

Potential Mitigations

References