HTTP Request Smuggling Affecting io.netty:netty-codec-http2 package, versions [,4.1.60.Final)



    Attack Complexity High
    Integrity High

    Threat Intelligence

    Exploit Maturity Mature
    EPSS 92.17% (99th percentile)
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5.9 medium
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Red Hat
5.9 medium

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  • Snyk ID SNYK-JAVA-IONETTY-1083991
  • published 10 Mar 2021
  • disclosed 10 Mar 2021
  • credit Unknown

How to fix?

Upgrade io.netty:netty-codec-http2 to version 4.1.60.Final or higher.


io.netty:netty-codec-http2 is a HTTP2 sub package for the netty library, an event-driven asynchronous network application framework.

Affected versions of this package are vulnerable to HTTP Request Smuggling. If a Content-Length header is present in the original HTTP/2 request, the field is not validated by Http2MultiplexHandler as it is propagated up.

An additional case of this vulnerability was fixed in 4.1.61.Final (CVE-2021-21409).