Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Netty | Netty | < 4.1.125 |
Related Weaknesses (CWE)
References
- https://datatracker.ietf.org/doc/html/rfc9112#name-chunked-transfer-codingTechnical Description
- https://github.com/JLLeitschuh/unCVEed/issues/1Issue TrackingThird Party Advisory
- https://github.com/netty/netty/commit/edb55fd8e0a3bcbd85881e423464f585183d1284Patch
- https://github.com/netty/netty/issues/15522Issue Tracking
- https://github.com/netty/netty/pull/15611Issue TrackingPatch
- https://github.com/netty/netty/security/advisories/GHSA-fghv-69vj-qj49ExploitVendor Advisory
- https://w4ke.info/2025/06/18/funky-chunks.htmlBroken Link
FAQ
What is CVE-2025-58056?
CVE-2025-58056 is a vulnerability with a CVSS score of 7.5 (HIGH). 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...
How severe is CVE-2025-58056?
CVE-2025-58056 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2025-58056?
Check the references section above for vendor advisories and patch information. Affected products include: Netty Netty.