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VULNERABILITIES

CVE-2026-56817 Details

Description

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.

Metrics

CVSS 3.x Severity and Vector Strings:

NIST: [email protected]CVSS-B:9.8 CRITICALVector:CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

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URLSource(s)Tag(s)
https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b [email protected]Patch
https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6 [email protected]Patch
https://github.com/netty/netty/releases/tag/netty-4.1.136.Final [email protected]Release Notes
https://github.com/netty/netty/releases/tag/netty-4.2.16.Final [email protected]Release Notes
https://github.com/netty/netty/security/advisories/GHSA-4qhr-g3c6-fcfx [email protected]Vendor Advisory

Weakness Enumeration

CWE-IDCWE NameSource
CWE-611Improper Restriction of XML External Entity Reference[email protected]

Affected Products

ProductVersions
netty netty
>= 4.1.0, < 4.1.136
>= 4.2.0, < 4.2.16

CPE

  • cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*

Remediation

  • No remediation found in references.

Change History

3 change records found show changes

QUICK INFO

CVE Dictionary Entry:
CVE-2026-56817
NVD Published Date:
Jul 21, 2026
NVD Last Modified:
Jul 30, 2026
Source:
[email protected]
CVE-2026-56817 Details - Not Deferred