CVE-2024-3884 Undertow: outofmemory when parsing form data encoding with application/x-www-form-urlencoded
Remote attackers can cause a denial of service by sending large form data, triggering an OutOfMemory error in the Undertow server.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-3884?
CVE-2024-3884 is a high-severity denial of service vulnerability in Red Hat OpenShift Serverless, published on 3 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A flaw was found in Undertow that can cause remote denial of service attacks. When the server uses the FormEncodedDataDefinition.doParse(StreamSourceChannel) method to parse large form data encoding with application/x-www-form-urlencoded, the method will cause an OutOfMemory issue. This flaw allows unauthorized users to cause a remote denial of service (DoS) attack.
Weakness: CWE-20
Which versions are affected by CVE-2024-3884?
6 open source packages ship an affected version, including io.undertow:undertow-core.
| Package | Affected | Fixed in |
|---|---|---|
io.undertow:undertow-core Maven | All versions | 2.2.39.Final |
io.undertow:undertow-core Maven | All versions | 2.2.39.Final |
io.undertow:undertow-core Maven | From 2.3.0.Alpha1 | 2.3.21.Final |
io.undertow:undertow-core Maven | From 2.3.0.Alpha1 | 2.3.21.Final |
io.undertow:undertow-core Maven | From 2.4.0.Alpha1 | 2.4.0.Beta1 |
io.undertow:undertow-core Maven | From 2.4.0.Alpha1 | 2.4.0.Beta1 |
How do I fix CVE-2024-3884?
Upgrade io.undertow:undertow-core to a fixed version for your release line: 2.2.39.Final, 2.3.21.Final or 2.4.0.Beta1.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2024-3884 being exploited?
There is no known exploitation of CVE-2024-3884 in the wild and no public exploit code.
Sources
Also known as CLSA-2026-1793128572, DEBIAN-CVE-2024-3884, GHSA-6h4f-pj3g-q8fq, UBUNTU-CVE-2024-3884.