CVE-2026-33871
HIGHNetty HTTP/2 CONTINUATION Frame Flood DoS via Zero-Byte Frame Bypass
Title source: cnaDescription
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.
Scores
CVSS v3
7.5
EPSS
0.0003
EPSS Percentile
7.7%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
yes
Technical Impact
partial
Details
CWE
CWE-770
Status
published
Products (4)
io.netty/netty-codec-http2
0 - 4.1.132.FinalMaven
netty/netty
< 4.1.132
netty/netty
< 4.1.132.Final
netty/netty
>= 4.2.0.Alpha1, < 4.2.10.Final
Published
Mar 27, 2026
Tracked Since
Mar 29, 2026