HTTP Request Smuggling Affecting netty package, versions *


Severity

Recommended
0.0
high
0
10

Snyk's Security Team recommends NVD's CVSS assessment. Learn more

Threat Intelligence

EPSS
0.24% (14th percentile)

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  • Snyk IDSNYK-DEBIAN12-NETTY-20154349
  • published27 Sept 2026
  • disclosed26 Sept 2026

Introduced: 26 Sep 2026

NewCVE-2026-100666  (opens in a new tab)
CWE-444  (opens in a new tab)

How to fix?

There is no fixed version for Debian:12 netty.

NVD Description

Note: Versions mentioned in the description apply only to the upstream netty package and not the netty package as distributed by Debian. See How to fix? for Debian:12 relevant fixed versions and status.

Netty's HttpServerCodec (io.netty:netty-codec-http) in versions 4.2.0.Final through 4.2.16.Final and in versions up to and including 4.1.136.Final pairs each outbound response with an inbound request by calling pollMethod() once per response, including for 1xx informational responses. If a client pipelines an HTTP/1.1 GET carrying an Expect: 100-continue header followed by a HEAD request, the 100 Continue response consumes the queued GET method, so the subsequent 200 OK for the GET is paired with HEAD and its body is dropped, while the following 200 OK for the HEAD request is written with a body. This desynchronizes HTTP parsing on the connection: the GET entity is never delivered and the HEAD response body is interpreted as the GET body, resulting in response splitting and unsafe connection reuse. Fixed in 4.2.17.Final and 4.1.137.Final.

CVSS Base Scores

version 3.1