A flaw was found in Undertow. When Undertow receives an HTTP request where the first header line starts with one or more spaces, it incorrectly processes the request by stripping these leading spaces. This behavior, which violates HTTP standards, can be exploited by a remote attacker to perform request smuggling. Request smuggling allows an attacker to bypass security mechanisms, access restricted information, or manipulate web caches, potentially leading to unauthorized actions or data exposure.

A flaw was found in Undertow. This vulnerability allows a remote attacker to construct specially crafted requests where header names are parsed differently by Undertow compared to upstream proxies. This discrepancy in header interpretation can be exploited to launch request smuggling attacks, potentially bypassing security controls and accessing unauthorized resources.

A flaw was found in Undertow. A remote attacker can exploit this vulnerability by sending \r\r\r as a header block terminator. This can be used for request smuggling with certain proxy servers, such as older versions of Apache Traffic Server and Google Cloud Classic Application Load Balancer, potentially leading to unauthorized access or manipulation of web requests.

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.

Impact

A flaw was found in Wildfly Elytron integration. The component does not implement sufficient measures to prevent multiple failed authentication attempts within a short time frame, making it more susceptible to brute force attacks via CLI.

Patches

The default behaviour has been changed in WildFly Core 31.0.3.Final, and 32.0.0.Beta3 - the first version is used by WildFly 39.0.1.Final and the second will be included in WildFly 40.

Workarounds

No direct workaround. Monitoring network traffic / blocking suspicious traffic may help.

References

https://www.cve.org/CVERecord?id=CVE-2025-23368 https://issues.redhat.com/browse/WFCORE-7192

Acknowledgements

We would like to thank Claudia Bartolini (TIM S.p.A), Marco Ventura (TIM S.p.A), and Massimiliano Brolli (TIM S.p.A) for reporting this issue.

It was found that a flaw in commons-collection library allowed remote code execution wherever deserialization occurs. While JBoss doesnt expose the JMXInvokerServlet by default, other interfaces where deserialization occur might be vulnerable.

Note: classes directly referenced by this flaw: InvokerTransformer, InstantiateFactory, and InstantiateTransformer

External References:

http://foxglovesecurity.com/2015/11/06/what-do-weblogic-websphere-jboss-jenkins-opennms-and-your-application-have-in-common-this-vulnerability/ https://access.redhat.com/solutions/2045023