CVE-2024-4027Network attack vector

Unauthenticated service crash via unbounded parameter names

Published Jan 30, 2026 · Updated Jan 30, 2026

Denial of service in Undertow servlets in affected Red Hat products allows remote attackers to crash services with oversized parameter names. HttpServletRequestImpl.getParameterNames() materializes attacker-controlled names while the default maximum entity size is unlimited, allowing heap allocation to end in OutOfMemoryError. Any unauthenticated request path backed by a servlet that invokes this method can exhaust the JVM heap and interrupt the hosting service; other endpoints are not established as reachable.

CVSS severity7.5
High
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Undertow servlets in affected Red Hat products allows remote attackers to crash services with oversized parameter names. HttpServletRequestImpl.getParameterNames() materializes attacker-controlled names while the default maximum entity size is unlimited, allowing heap allocation to end in OutOfMemoryError. Any unauthenticated request path backed by a servlet that invokes this method can exhaust the JVM heap and interrupt the hosting service; other endpoints are not established as reachable.

The record

CVE
CVE-2024-4027
Published
Jan 30, 2026
Updated
Jan 30, 2026
Vendor
389 Directory Server
Product
Red Hat build of Apicurio Registry 2
Classifications
CWE-20, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 30, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

389 Directory Server · Red Hat build of Apicurio Registry 2Affected versions are unavailable in this record.
389 Directory Server · Red Hat Integration - Camel KAffected versions are unavailable in this record.
389 Directory Server · Red Hat Fuse 7Affected versions are unavailable in this record.
389 Directory Server · Red Hat Process Automation Manager 7Affected versions are unavailable in this record.

Published CVSS scores

7.5Red HatCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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