PT-2021-5814 · Unknown+7 · Io.Netty:Netty-Codec-Http2+7

Published

2021-01-21

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Updated

2026-04-01

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CVE-2021-21295

CVSS v3.1

5.9

Medium

VectorAV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Name of the Vulnerable Software and Affected Versions io.netty:netty-codec-http2 versions prior to 4.1.60.Final
Description The issue is related to the handling of HTTP/2 requests in the Netty framework, specifically when the Content-Length header is present. If a request comes in as an HTTP/2 stream and is converted to HTTP/1.1 domain objects via Http2StreamFrameToHttpObjectCodec, it may result in request smuggling when proxied through a remote peer as HTTP/1.1. An attacker can smuggle requests inside the body as it gets downgraded from HTTP/2 to HTTP/1.1. Users are only affected if 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.
Recommendations For versions prior to 4.1.60.Final, update to version 4.1.60.Final or later to resolve the issue. As a temporary workaround, users can implement a custom ChannelInboundHandler that is put in the ChannelPipeline behind Http2StreamFrameToHttpObjectCodec to perform the validation themselves.

Fix

DoS

HTTP Request/Response Smuggling

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Weakness Enumeration

Related Identifiers

BDU:2022-00303
BIT-ZOOKEEPER-2021-21295
CLEANSTART-2026-CI66802
CVE-2021-21295
DSA-4885-1
GHSA-F256-J965-7F32
GHSA-WM47-8V5P-WJPJ
MGASA-2021-0374
OESA-2021-1161
OPENSUSE-SU-2021:0448-1
OPENSUSE-SU-2021_0448-1
OPENSUSE-SU-2022_1271-1
OPENSUSE-SU-2024:11085-1
RHSA-2021:1511
RHSA-2021:2046
RHSA-2021:2047
RHSA-2021:2048
RHSA-2021:3656
RHSA-2021:3658
RHSA-2022:5498
RLSA-2022:5498
SUSE-SU-2022:1271-1
USN-6049-1

Affected Products

Apache Zookeeper
Astra Linux
Linuxmint
Red Os
Rocky Linux
Suse
Ubuntu
Io.Netty:Netty-Codec-Http2