CVE-2026-33871

High

Description

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.

SeverityHigh

CVSS7.5

Exploit probability—

ProductNetty

PublishedMar 27, 2026

First seenMar 27, 2026

Weakness typeCWE-770Allocation of resources without limits

How to fix

Update

netty netty4.1.132, 4.2.10 or later
io.netty:netty-codec-http24.1.132.Final, 4.2.11.Final or later

Vendor advisories

Affected products

Product	Affected versions	Fixed in
netty netty	v < 4.1.132, 4.2.0 ≤ v < 4.2.10	4.1.132, 4.2.10
io.netty:netty-codec-http2Maven	v < 4.1.132.Final, 4.2.0.Alpha1 ≤ v < 4.2.11.Final	4.1.132.Final, 4.2.11.Final

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

In the Intelligence 360 plan

Attack Surface Management

See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.