critical9.8
CVE-2026-56817
Netty XML: Injection / Risky Sink — unconfigured XML factory with active DTD and entity handling
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| maven | io.netty:netty-codec-xml | >= 4.2.0.Final, <= 4.2.15.Final | 4.2.16.Final |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Netty | Netty | from 4.1.0 before 4.1.136 from 4.2.0 before 4.2.16 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-4qhr-g3c6-fcfx
- https://github.com/netty/netty/security/advisories/GHSA-4qhr-g3c6-fcfx
- https://nvd.nist.gov/vuln/detail/CVE-2026-56817
- https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b
- https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6
- https://github.com/netty/netty/releases/tag/netty-4.1.136.Final
- https://github.com/netty/netty/releases/tag/netty-4.2.16.Final