GitHub Advisoryadvisory · Maven

GHSA-4qhr-g3c6-fcfx Netty XML: Injection / Risky Sink — unconfigured XML factory with active DTD and entity handling

HIGH Published 2026-07-22 Modified 2026-07-22 Official page ↗
Aliases
CVE-2026-56817
Ecosystem
Maven
Packages
io.netty:netty-codec-xml
Severity
High
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:L/SC:N/SI:N/SA:N
Weaknesses
CWE-611
Reviewed
2026-07-22

Affected packages

• Maven io.netty:netty-codec-xml: >= 4.2.0.Final, < 4.2.16.Final → fixed in 4.2.16.Final • Maven io.netty:netty-codec-xml: >= 4.1.0.Final, < 4.1.136.Final → fixed in 4.1.136.Final

Description

Any caller that can deliver bytes to a Netty channel pipeline containing `XmlDecoder` can send XML with a DOCTYPE declaration to a parser instantiated with no security configuration — but whether external entities are actually resolved depends on Aalto XML's async parser behavior, making this a confirmed misconfiguration with conditional exploitability.

Related

Alias · CVE (1)

  • CVE-2026-56817 Netty is a network application framework for development of protocol servers and clients. vulnerability

Weakness · CWE (1)

  • CWE-611 Improper Restriction of XML External Entity Reference weakness

References