CVE-2025-58056
HIGHDescription
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 v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Exploit Intelligence
Moderate risk: more likely to be exploited than 46% of all known CVEs.
References
- https://datatracker.ietf.org/doc/html/rfc9112#name-chunked-transfer-coding
- https://github.com/JLLeitschuh/unCVEed/issues/1
- https://github.com/netty/netty/commit/edb55fd8e0a3bcbd85881e423464f585183d1284
- https://github.com/netty/netty/issues/15522
- https://github.com/netty/netty/pull/15611
- https://github.com/netty/netty/security/advisories/GHSA-fghv-69vj-qj49
- https://w4ke.info/2025/06/18/funky-chunks.html
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Start freeThis product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-09-08.