QID 980339

QID 980339: Java (maven) Security Update for io.netty:netty-codec-http2 (GHSA-wm47-8v5p-wjpj)

Security update has been released for io.netty:netty-codec-http2 to fix the vulnerability.

Note: The preceding description block is extracted directly from the security advisory. Using automation, we have attempted to clean and format it as much as possible without introducing additional issues.

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. This is fine as long as the request is not proxied through as HTTP/1.1.
If the request comes in as an HTTP/2 stream, gets converted into the HTTP/1.1 domain objects (`HttpRequest`, `HttpContent`, etc.) via `Http2StreamFrameToHttpObjectCodec `and then sent up to the child channel's pipeline and proxied through a remote peer as HTTP/1.1 this may result in request smuggling.

In a proxy case, users may assume the content-length is validated somehow, which is not the case. If the request is forwarded to a backend channel that is a HTTP/1.1 connection, the Content-Length now has meaning and needs to be checked.

An attacker can smuggle requests inside the body as it gets downgraded from HTTP/2 to HTTP/1.1. A sample attack request looks like:

```
POST / HTTP/2
:authority:: externaldomain.com
Content-Length: 4

asdfGET /evilRedirect HTTP/1.1
Host: internaldomain.com
```

Users are only affected if all of this is `true`:
* `HTTP2MultiplexCodec` or `Http2FrameCodec` is used
* `Http2StreamFrameToHttpObjectCodec` is used to convert to HTTP/1.1 objects
* These HTTP/1.1 objects are forwarded to another remote peer.

  • CVSS V3 rated as Medium - 5.9 severity.
  • CVSS V2 rated as Low - 2.6 severity.
  • Solution
    This has been patched in 4.1.60.FinalWorkaround:
    The user can do the validation by themselves by implementing a custom `ChannelInboundHandler` that is put in the `ChannelPipeline` behind `Http2StreamFrameToHttpObjectCodec`.
    Vendor References

    CVEs related to QID 980339

    Software Advisories
    Advisory ID Software Component Link
    GHSA-wm47-8v5p-wjpj io.netty:netty-codec-http2 URL Logo github.com/advisories/GHSA-wm47-8v5p-wjpj
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