CVE-2026-56817

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.

CVSS v3 9.8 CRITICAL

9.8^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b	Patch
https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6	Patch
https://github.com/netty/netty/releases/tag/netty-4.1.136.Final	Release Notes
https://github.com/netty/netty/releases/tag/netty-4.2.16.Final	Release Notes
https://github.com/netty/netty/security/advisories/GHSA-4qhr-g3c6-fcfx	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:netty:netty::::::::
	cpe:2.3:a:netty:netty::::::::

History

No history.

Information

Published : 2026-07-21 23:17

Updated : 2026-07-30 14:48

NVD link : CVE-2026-56817

Mitre link : CVE-2026-56817

CVE.ORG link : CVE-2026-56817

JSON object : View

Products Affected

netty

netty

CWE

CWE-611

Improper Restriction of XML External Entity Reference

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