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.
History

Wed, 03 Sep 2025 21:00:00 +0000

Type Values Removed Values Added
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.
Title Netty is vulnerable to request smuggling due to incorrect parsing of chunk extensions
Weaknesses CWE-444
References
Metrics cvssV4_0

{'score': 8.2, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2025-09-03T20:56:50.732Z

Reserved: 2025-08-22T14:30:32.221Z

Link: CVE-2025-58056

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2025-09-03T21:15:33.070

Modified: 2025-09-03T21:15:33.070

Link: CVE-2025-58056

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.