CVE-2026-33871: Netty

High severity, CVSS 7.5. EPSS: 1.2% chance of exploitation in the next 30 days.

Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.132.Final and 4.2.10.Final, a remote user can trigger a Denial of Service (DoS) against a Netty HTTP/2 server by sending a flood of `CONTINUATION` frames. The server's lack of a limit on the number of `CONTINUATION` frames, combined with a bypass of existing size-based mitigations using zero-byte frames, allows an user to cause excessive CPU consumption with minimal bandwidth, rendering the server unresponsive. Versions 4.1.132.Final and 4.2.10.Final fix the issue.

Affected products

• Netty Netty: before 4.1.132 (fixed in 4.1.132); from 4.2.0, before 4.2.10 (fixed in 4.2.10)

Published 2026-03-27. Last modified 2026-09-14.