Summaryinfo

A vulnerability, which was classified as critical, has been found in Netty up to 1.1/4.1.132.Final/4.2.10.Final. This impacts an unknown function. Performing a manipulation results in request smuggling. This vulnerability was named CVE-2026-33870. The attack may be initiated remotely. There is no available exploit. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in Netty up to 1.1/4.1.132.Final/4.2.10.Final. This affects an unknown functionality. The manipulation with an unknown input leads to a request smuggling vulnerability. CWE is classifying the issue as CWE-444. The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.132.Final and 4.2.10.Final, Netty incorrectly parses quoted strings in HTTP/1.1 chunked transfer encoding extension values, enabling request smuggling attacks. Versions 4.1.132.Final and 4.2.10.Final fix the issue.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-33870 since 03/24/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Neither technical details nor an exploit are publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 304176 (Linux Distros Unpatched Vulnerability : CVE-2026-33870), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 4.1.132.Final or 4.2.10.Final eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (304176). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Name

• Netty

Version

• 1.0
• 1.1
• 4.1.132.Final
• 4.2.10.Final

Website

• Product: https://github.com/netty/netty/

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