DEBIAN-CVE-2021-21295

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Source
https://security-tracker.debian.org/tracker/CVE-2021-21295
Import Source
https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2021-21295.json
JSON Data
https://api.test.osv.dev/v1/vulns/DEBIAN-CVE-2021-21295
Upstream
Published
2021-03-09T19:15:12Z
Modified
2025-09-19T06:22:27Z
Summary
[none]
Details

Netty is an open-source, asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients. In Netty (io.netty:netty-codec-http2) before version 4.1.60.Final there is a vulnerability that enables 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. 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 Http2StreamFrameToHttpObjectCodecand 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. For an example attack refer to the linked GitHub Advisory. 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, and these HTTP/1.1 objects are forwarded to another remote peer. This has been patched in 4.1.60.Final As a workaround, the user can do the validation by themselves by implementing a custom ChannelInboundHandler that is put in the ChannelPipeline behind Http2StreamFrameToHttpObjectCodec.

References

Affected packages

Debian:11 / netty

Package

Name
netty
Purl
pkg:deb/debian/netty?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1:4.1.48-3

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Debian:12 / netty

Package

Name
netty
Purl
pkg:deb/debian/netty?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1:4.1.48-3

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Debian:13 / netty

Package

Name
netty
Purl
pkg:deb/debian/netty?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1:4.1.48-3

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Debian:14 / netty

Package

Name
netty
Purl
pkg:deb/debian/netty?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1:4.1.48-3

Ecosystem specific 

{
    "urgency": "not yet assigned"
}