CVE-2026-42580: Netty

Medium severity, CVSS 6.5. EPSS: 0.4% chance of exploitation in the next 30 days.

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.

Affected products

• Netty Netty: before 4.1.133 (fixed in 4.1.133); from 4.2.0, before 4.2.13 (fixed in 4.2.13)

Published 2026-05-13. Last modified 2026-06-17.