# CVE-2024-4027: Red Hat Undertow denial of service via OutOfMemoryError in getParameterNames

Source: https://junglewise.ai/threats/cve-2024-4027-red-hat-undertow-denial-of-service-via-outofmemoryerror-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-01-30. Updated: 2026-06-30  
License: CC BY 4.0 with a link back

CVE-2024-4027 · Severity: high · CVSS 7.5 · Published 2026-01-30

Undertow is a flexible web server used in many Java-based applications and Red Hat products. A flaw allows an unauthorized remote attacker to crash the server by sending a request with excessively large parameter names. This results in a denial-of-service, making the affected application or service unavailable to legitimate users.

Technologies: [io.undertow:undertow-core (Maven)](https://junglewise.ai/threats/technologies/io-undertow-undertow-core), [Red Hat build of Apicurio Registry 2](https://junglewise.ai/threats/technologies/apicurio-registry-3), [Red Hat Fuse 7](https://junglewise.ai/threats/technologies/fuse-7). Vendors: [Maven](https://junglewise.ai/threats/vendors/maven), [Red Hat](https://junglewise.ai/threats/vendors/red-hat).

## Quick answers

**Is CVE-2024-4027 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2024-4027 being exploited in the wild.

**How severe is CVE-2024-4027?** High severity, with a CVSS score of 7.5, published 30 January 2026.

**Which products and versions are affected?** io.undertow:undertow-core (Maven) ECOSYSTEM:introduced=0,fixed=2.2.39.Final.

**Is there a fix for CVE-2024-4027?** Yes. io.undertow:undertow-core (Maven): upgrade to 2.2.39.Final or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2024-4027 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2024-4027?** Check whether you run io.undertow:undertow-core (Maven), Red Hat build of Apicurio Registry 2, Red Hat Fuse 7 or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- io.undertow:undertow-core (Maven): upgrade to 2.2.39.Final or later

  ```sh
  # set io.undertow:undertow-core to 2.2.39.Final in your pom.xml or build.gradle
  ```


## Technical details

A vulnerability exists in Undertow's HttpServletRequestImpl.getParameterNames() method due to improper input validation of request parameters. An unauthenticated remote attacker can send a specially crafted HTTP request containing extremely large parameter names. When a servlet calls the affected method to process these parameters, it triggers an OutOfMemoryError (OOM), causing the Java Virtual Machine (JVM) to crash or become unresponsive. This results in a denial-of-service (DoS) condition for any application using the vulnerable Undertow library.

## Affected products

- Red Hat Undertow
- Red Hat Red Hat build of Quarkus
- Red Hat Red Hat build of Apicurio Registry 2
- Red Hat Red Hat Fuse 7
- Red Hat Red Hat Integration Camel K 1
- Red Hat Red Hat JBoss Data Grid 7
- Red Hat Red Hat JBoss Fuse Service Works 6
- Red Hat Red Hat Process Automation 7
- Red Hat OpenShift Serverless

## Identifiers

- CVE-2024-4027
- GHSA-33hj-rcmx-86mv

## Timeline

- 2024-01-01: disclosed
- 2026-01-30: advisory

## References

- [https://access.redhat.com/downloads/content/package-browser/](https://access.redhat.com/downloads/content/package-browser/)
- [https://access.redhat.com/jbossnetwork/restricted/listSoftware.html](https://access.redhat.com/jbossnetwork/restricted/listSoftware.html)
- [https://access.redhat.com/security/cve/CVE-2024-4027](https://access.redhat.com/security/cve/CVE-2024-4027)
- [https://bugzilla.redhat.com/show_bug.cgi?id=2276410](https://bugzilla.redhat.com/show_bug.cgi?id=2276410)
- [https://security.access.redhat.com/data/csaf/v2/vex/2024/cve-2024-4027.json](https://security.access.redhat.com/data/csaf/v2/vex/2024/cve-2024-4027.json)

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