Is there a public exploit for CVE-2025-12543?

No public exploit for CVE-2025-12543 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2025-12543?

CVE-2025-12543 scores CVSS 9.6 (v3.1), rated critical. EPSS puts the chance of exploitation in the next 30 days at 1.33%.

What does CVE-2025-12543 affect?

CVE-2025-12543 affects Red Hat Red Hat JBoss Enterprise Application Platform 8.0 for RHEL 8, Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 8, Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9, Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 9, Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8, Red Hat JBoss Enterprise Application Platform 7.4.24.

9.6 Critical

A flaw was found in the Undertow HTTP server core, which is used in WildFly, JBoss EAP, and other Java applications.

CVE-2025-12543

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.

Assessment

CVSS: 9.6 (v3.1)
Severity: Critical
EPSS: 1.33% chance of exploitation in the next 30 days
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 7 January 2026
Last updated: 4 November 2026
Affected: Red Hat · RHEL-8 based Middleware Containers · Red Hat JBoss Enterprise Application Platform 7.1 EUS for RHEL 7 · Red Hat JBoss Enterprise Application Platform 7.3 EUS for RHEL 7 · Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 7
Assigner: redhat

CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:L

At the source

EUVD (ENISA)

References

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