HTTP Request Smuggling Affecting netty package, versions <1:4.1.48-16ubuntu0.1~esm2


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.02% (5th percentile)

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  • Snyk IDSNYK-UBUNTU2604-NETTY-16781414
  • published3 Jun 2026
  • disclosed13 May 2026

Introduced: 13 May 2026

CVE-2026-42584  (opens in a new tab)
CWE-444  (opens in a new tab)

How to fix?

Upgrade Ubuntu:26.04 netty to version 1:4.1.48-16ubuntu0.1~esm2 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream netty package and not the netty package as distributed by Ubuntu. See How to fix? for Ubuntu:26.04 relevant fixed versions and status.

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpClientCodec pairs each inbound response with an outbound request by queue.poll() once per response, including for 1xx. If the client pipelines GET then HEAD and the server sends 103, then 200 with GET body, then 200 for HEAD, the queue pairs HEAD with the first 200. The HEAD rule then skips reading that message’s body, so the GET entity bytes stay on the stream and the following 200 is parsed from the wrong offset. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

CVSS Base Scores

version 3.1