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CVE-2026-33871

HIGH CVSS 4.0: 8.7 EPSS 0.08%
Updated Mar 30, 2026
Netty
Parameter Value
CVSS 8.7 (HIGH)
Affected Versions 4.2.0 — 4.2.10
Fixed In 4.1.132
Type CWE-770 (Allocation Without Limits)
Vendor Netty
Public PoC No

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.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
High
Complete denial of service

CVSS Vector v4.0

Vulnerable Products 2

Configuration From (including) Up to (excluding)
Netty Netty
cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*
4.1.132
Netty Netty
cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*
4.2.0 4.2.10