Low 2.9Published Sep 3, 2025

CVE-2025-58056Netty is vulnerable to request smuggling due to incorrect parsing of chunk extensions

Updated under an hour ago (Oct 28, 2026, 2:23 AM ET)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

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.

CVSS: 2.9 LOW (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P
Weakness (CWE): CWE-444
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Sep 5, 2025
First seen by InfoSec Signals: Oct 19, 2026

Affected products

Affected products

netty netty netty:netty (from the name)	from 4.2.0.Alpha3, < 4.2.5.Final; through 4.1.124.Final, < 4.1.125.Final	CNA record
netty netty netty:netty	before 4.1.125; from 4.2.0 before 4.2.5	NVD

References

References

https://github.com/netty/netty/security/advisories/GHSA-fghv-69vj-qj49	x-refsource-confirm, exploit, vendor-advisory
https://github.com/JLLeitschuh/unCVEed/issues/1	x-refsource-misc, issue-tracking, third-party-advisory
https://github.com/netty/netty/issues/15522	x-refsource-misc, issue-tracking
https://github.com/netty/netty/pull/15611	x-refsource-misc, issue-tracking, patch
https://github.com/netty/netty/commit/edb55fd8e0a3bcbd85881e423464f585183d1284	x-refsource-misc, patch
https://datatracker.ietf.org/doc/html/rfc9112#name-chunked-transfer-coding	x-refsource-misc, technical-description
https://w4ke.info/2025/06/18/funky-chunks.html	x-refsource-misc, broken-link

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.