Netty Before 4.1.124/4.2.4 – DDoS via HTTP/2 Frame Exploit
CVE-2025-55163 Published on August 13, 2025
Netty MadeYouReset HTTP/2 DDoS Vulnerability
Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.124.Final and 4.2.4.Final, Netty is vulnerable to MadeYouReset DDoS. This is a logical vulnerability in the HTTP/2 protocol, that uses malformed HTTP/2 control frames in order to break the max concurrent streams limit - which results in resource exhaustion and distributed denial of service. This issue has been patched in versions 4.1.124.Final and 4.2.4.Final.
Weakness Type
Allocation of Resources Without Limits or Throttling
The software allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor.
Products Associated with CVE-2025-55163
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Affected Versions
netty:- Version < 4.1.124.Final is affected.
- Version < 4.2.4.Final is affected.
Vulnerable Packages
The following package name and versions may be associated with CVE-2025-55163
| Package Manager | Vulnerable Package | Versions | Fixed In |
|---|---|---|---|
| maven | io.netty:netty-codec-http2 | >= 4.2.0.Alpha1, <= 4.2.3.Final | 4.2.4.Final |
| maven | io.netty:netty-codec-http2 | <= 4.1.123.Final | 4.1.124.Final |
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.