CVE-2025-58056
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-09-03

Last updated on: 2025-09-08

Assigner: GitHub, Inc.

Description
Netty is an asynchronous event-driven network application framework for development of maintainable high performance protocol servers and clients. In versions 4.1.124.Final, and 4.2.0.Alpha3 through 4.2.4.Final, Netty incorrectly accepts standalone newline characters (LF) as a chunk-size line terminator, regardless of a preceding carriage return (CR), instead of requiring CRLF per HTTP/1.1 standards. When combined with reverse proxies that parse LF differently (treating it as part of the chunk extension), attackers can craft requests that the proxy sees as one request but Netty processes as two, enabling request smuggling attacks. This is fixed in versions 4.1.125.Final and 4.2.5.Final.
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Meta Information
Published
2025-09-03
Last Modified
2025-09-08
Generated
2026-05-07
AI Q&A
2025-09-04
EPSS Evaluated
2026-05-05
NVD
Affected Vendors & Products
Showing 2 associated CPEs
Vendor Product Version / Range
netty netty to 4.1.125 (exc)
netty netty From 4.2.0 (inc) to 4.2.5 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
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.
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability occurs in Netty versions 4.1.124.Final and 4.2.0.Alpha3 through 4.2.4.Final, where Netty incorrectly accepts standalone newline characters (LF) as a chunk-size line terminator instead of requiring the proper carriage return followed by a newline (CRLF) as per HTTP/1.1 standards. This discrepancy allows attackers to craft requests that are interpreted differently by reverse proxies and Netty, enabling HTTP request smuggling attacks.


How can this vulnerability impact me? :

The vulnerability can allow attackers to perform HTTP request smuggling attacks by sending specially crafted requests that are parsed differently by reverse proxies and Netty servers. This can lead to security issues such as bypassing security controls, unauthorized access, or manipulation of requests and responses.


What immediate steps should I take to mitigate this vulnerability?

Upgrade Netty to version 4.1.125.Final or 4.2.5.Final or later, as these versions contain the fix for this vulnerability.


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