CVE-2025-11538 is a security vulnerability identified in the Red Hat Build of Keycloak, a widely used open-source identity and access management solution. The issue arises when the server is started with debug mode enabled using the '--debug <port>' option. By default, this configuration causes the Java Debug Wire Protocol (JDWP) port to bind to all network interfaces (0.0.0.0), rather than restricting it to localhost. JDWP is a protocol used for remote debugging of Java applications, and exposing it to the network allows any user on the same local network segment to connect to the Keycloak JVM's debug port. Since JDWP does not enforce authentication by default, an attacker can attach a remote debugger, gaining the ability to execute arbitrary code within the JVM process running Keycloak. This can lead to full compromise of the Keycloak server, including unauthorized access to sensitive authentication and authorization data, manipulation of identity tokens, or disruption of service. The vulnerability does not require prior authentication or user interaction but does require network access to the exposed debug port. The CVSS 3.1 score is 6.8 (medium severity), reflecting the attack vector as adjacent network (AV:A), high attack complexity (AC:H), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), and high impact on confidentiality and integrity (C:H/I:H/A:N). No known exploits are reported in the wild as of the publication date (November 13, 2025). The vulnerability highlights a misconfiguration risk when enabling debug mode in production or semi-production environments without proper network restrictions or binding configurations.

For European organizations, the exposure of the JDWP debug port on Keycloak servers can lead to severe security breaches. Keycloak often manages critical identity and access management functions, so compromise can result in unauthorized access to internal applications, user credentials, and sensitive personal data protected under GDPR. Confidentiality and integrity of authentication tokens and user sessions can be undermined, potentially allowing attackers to impersonate users or escalate privileges. Although the vulnerability requires network adjacency, many enterprise environments have flat or insufficiently segmented networks, increasing risk. The lack of authentication on the debug port means that once accessed, attackers can execute arbitrary code, potentially leading to persistent backdoors or lateral movement within the network. This could disrupt business operations and damage trust with customers and partners. The medium CVSS score may underestimate the real-world impact if debug mode is enabled in production environments without proper safeguards.

To mitigate CVE-2025-11538, organizations should first ensure that debug mode is disabled in all production and sensitive environments. If debugging is necessary, configure the JDWP port to bind exclusively to localhost (127.0.0.1) to prevent remote network access. Network-level controls such as firewall rules or VLAN segmentation should be applied to restrict access to the debug port strictly to trusted hosts. Monitoring network traffic for connections to JDWP ports can help detect unauthorized access attempts. Additionally, updating to patched versions of the Red Hat Build of Keycloak once available is critical. Security teams should audit existing Keycloak deployments for inadvertent debug mode activation and review startup scripts or container configurations. Implementing strict access controls and network segmentation around identity management infrastructure further reduces risk. Finally, educating developers and administrators about the risks of enabling debug mode in production environments is essential to prevent recurrence.