CVE-2024-29025

The HttpPostRequestDecoder can be tricked to accumulate data. I have spotted currently two attack vectors

Details

1. While the decoder can store items on the disk if configured so, there are no limits to the number of fields the form can have, an attacher can send a chunked post consisting of many small fields that will be accumulated in the bodyListHttpData list.
2. The decoder cumulates bytes in the undecodedChunk buffer until it can decode a field, this field can cumulate data without limits

PoC

Here is a Netty branch that provides a fix + tests : https://github.com/vietj/netty/tree/post-request-decoder

Here is a reproducer with Vert.x (which uses this decoder) https://gist.github.com/vietj/f558b8ea81ec6505f1e9a6ca283c9ae3

Any Netty based HTTP server that uses the HttpPostRequestDecoder to decode a form.

The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap. Typical impact: resource exhaustion leading to denial of service.

CVE-2024-29025 has a CVSS score of 5.3 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (4.1.108.Final); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2024-29025? CVE-2024-29025 is a medium-severity allocation of resources without limits or throttling vulnerability in io.netty:netty-codec-http (maven), affecting versions < 4.1.108.Final. It is fixed in 4.1.108.Final. The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap.
2. How severe is CVE-2024-29025? CVE-2024-29025 has a CVSS score of 5.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of io.netty:netty-codec-http are affected by CVE-2024-29025? io.netty:netty-codec-http (maven) versions < 4.1.108.Final is affected.
4. Is there a fix for CVE-2024-29025? Yes. CVE-2024-29025 is fixed in 4.1.108.Final. Upgrade to this version or later.
5. Is CVE-2024-29025 exploitable, and should I be worried? Whether CVE-2024-29025 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2024-29025 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2024-29025? Upgrade io.netty:netty-codec-http to 4.1.108.Final or later.