CVE-2025-12543 Red Hat CVE debrief

Who should care

Organizations using Red Hat products such as JBoss Enterprise Application Platform, Fuse, and Undertow should be aware of this vulnerability. Specifically, users of JBoss EAP versions 8.0, 8.1, and 7.0, as well as Fuse and Undertow, need to take action to mitigate this vulnerability. The vulnerability's high CVSS score and potential impact on cache poisoning, internal network scanning, and session hijacking make it a priority for defenders to address.

Technical summary

The Undertow library fails to properly validate the Host header in incoming HTTP requests, allowing requests with malformed or malicious Host headers to be processed without rejection. This enables attackers to poison caches, perform internal network scans, or hijack user sessions. The vulnerability affects multiple Red Hat products, including JBoss Enterprise Application Platform, Fuse, and Undertow. The CVSS vector for this vulnerability is CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:L.

Defensive priority

This vulnerability has a high defensive priority due to its critical CVSS score and potential impact on affected systems. Defenders should prioritize patching or mitigating this vulnerability as soon as possible to prevent potential attacks.

Recommended defensive actions

• Apply patches or updates provided by Red Hat to address the vulnerability in affected products.
• Review and update configurations for JBoss Enterprise Application Platform, Fuse, and Undertow to ensure they are not exposed to untrusted networks or users.
• Implement additional security controls, such as web application firewalls or intrusion detection systems, to detect and prevent potential attacks.
• Monitor systems for signs of exploitation, such as unusual cache activity or session hijacking attempts.
• Consider implementing compensating controls, such as validating Host headers at the application level, if patching is not feasible in the short term.

Evidence notes

The CVE-2025-12543 record and associated metadata were obtained from the National Vulnerability Database (NVD) and Red Hat's security advisories. The vulnerability affects multiple Red Hat products, including JBoss Enterprise Application Platform, Fuse, and Undertow. The CVSS score and vector were provided in the CVE record.

Official resources