CVE-2025-58056

Name	CVE-2025-58056
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.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs	1113995

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
netty (PTS)	bullseye (security), bullseye	1:4.1.48-4+deb11u2	vulnerable
	bookworm, bookworm (security)	1:4.1.48-7+deb12u1	vulnerable
	forky, sid, trixie	1:4.1.48-10	vulnerable

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
netty	source	(unstable)	(unfixed)			1113995

Notes

https://github.com/netty/netty/security/advisories/GHSA-fghv-69vj-qj49
https://github.com/netty/netty/issues/15522
https://github.com/netty/netty/pull/15611
https://github.com/netty/netty/commit/edb55fd8e0a3bcbd85881e423464f585183d1284 (netty-4.2.5.Final)