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CVE-2025-12543

Redhat Undertow vulnerability

9.6 CRITICALEPSS 1.33%
  1. Published7 Jan 2026

Description

A flaw was found in the Undertow HTTP server core, which is used in WildFly, JBoss EAP, and other Java applications. The Undertow library fails to properly validate the Host header in incoming HTTP requests.As a result, requests containing malformed or malicious Host headers are processed without rejection, enabling attackers to poison caches, perform internal network scans, or hijack user sessions.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionRequired
ScopeChanged
ConfidentialityHigh
IntegrityHigh
AvailabilityLow
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:L

Affected products

Redhat Build Of Apache Camel< 4.14.4
Redhat Data Grid8.0
Redhat Fuse7.0.0
Redhat Jboss Enterprise Application Platform≥ 8.0 < 8.0.12 · ≥ 8.1.0 < 8.1.3 · 7.0.0
Redhat Jboss Enterprise Application Platform Expansion Packall versions
Redhat Process Automation7.0
Redhat Single Sign-on7.0
Redhat Undertow≥ 2.3.0 < 2.3.21 · < 2.2.39

Remediation

Fixed in
Redhat Build Of Apache Camel≥ 4.14.4
Redhat Jboss Enterprise Application Platform≥ 8.0.12
Redhat Undertow≥ 2.3.21

References

and 11 more references

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Frequently asked

Is CVE-2025-12543 being actively exploited?

CVE-2025-12543 is not in the CISA KEV catalog. Its EPSS exploit probability is 1.33%.

How severe is CVE-2025-12543?

CVE-2025-12543 has a CVSS 3.1 base score of 9.6, rated critical. EPSS estimates a 1.33% probability of exploitation.

Which products are affected by CVE-2025-12543?

Affected products include Redhat Build Of Apache Camel, Redhat Data Grid, Redhat Fuse, Redhat Jboss Enterprise Application Platform, Redhat Jboss Enterprise Application Platform Expansion Pack, and 3 more.

How do I fix CVE-2025-12543?

Upgrade affected software to a fixed version, for example Redhat Build Of Apache Camel 4.14.4, Redhat Jboss Enterprise Application Platform 8.0.12, Redhat Undertow 2.3.21 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2025-12543 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.