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CVE-2026-56817GHSA-4QHR-G3C6-FCFX

Netty: XML External Entity (XXE) injection via unconfigured XML factory when DTD and entity processing are enabled

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 4.2.16.Final, 4.1.136.Final
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: yes
  • Technical impact: partial

Summary

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: yes · Technical impact: partial

  3. Record last updated

Affected versions

  • netty netty

    From 4.2.0.Final · fixed in 4.2.16.Final; From 4.1.0.Final · fixed in 4.1.136.Final

  • io.netty:netty-codec-xmlMaven

    From 4.2.0.Final · fixed in 4.2.16.Final

  • io.netty:netty-codec-xmlMaven

    From 4.1.0.Final · fixed in 4.1.136.Final

References 5

GitHub · netty/netty