CVE-2026-42580

Netty: HTTP Request Smuggling due to incorrect chunk size parsing

State: Published
Severity: 6.5 Medium
Published: May 13, 2026
Updated: May 14, 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's chunk size parser silently overflows int, 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:N/I:L/A:L	GitHub_M

Weaknesses

CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
CWE-190 Integer Overflow or Wraparound

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-m4cv-j2px-7723

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