CVE-2026-42585

Netty: HTTP Request Smuggling due to malformed Transfer-Encoding

State: Published
Severity: 6.5 Medium
Published: May 13, 2026
Updated: May 15, 2026
Reserved: Apr 28, 2026

Description

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty incorrectly parses malformed Transfer-Encoding, enabling request smuggling attacks. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

Scores

CVSS	Score	Vector	Source
3.1	6.5 Medium	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N	GitHub_M

Weaknesses

CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

Affected Products

Product	Versions
nettynetty	>= 4.2.0.Alpha1, < 4.2.13.FinalAffected < 4.1.133.FinalAffected
netty-codec-httpio.netty	>= 4.2.0.Alpha1, < 4.2.13.FinalAffected < 4.1.133.FinalAffected

References

https://github.com/netty/netty/security/advisories/GHSA-38f8-5428-x5cv

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