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.

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

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), Red Hat build of Apicurio Registry 2, Red Hat Fuse 7. Vendors: Maven, 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

# 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

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