Overview
CVE-2025-13467 is a medium-severity vulnerability affecting the LDAP User Federation provider in Keycloak. This flaw allows a malicious, authenticated realm administrator to trigger deserialization of untrusted Java objects through a specially crafted LDAP server configuration. Published on 2025-11-25T16:16:06.623, this vulnerability requires immediate attention from Keycloak administrators.
Technical Details
The vulnerability stems from insufficient validation of the LDAP server configuration within the Keycloak LDAP User Federation provider. An authenticated realm administrator, with the necessary permissions, can configure Keycloak to connect to a malicious LDAP server. This server can then return a specially crafted response containing serialized Java objects. Keycloak, without proper sanitization, attempts to deserialize these objects, potentially leading to remote code execution (RCE) or other malicious actions.
Specifically, the `java.naming.factory.object` LDAP attribute is used by a malicious LDAP server to specify a Java class to be instantiated. When Keycloak attempts to retrieve attributes from the LDAP server, it unintentionally deserializes the class specified. This can be exploited to trigger arbitrary code execution by providing a malicious class.
Example scenario:
// Vulnerable LDAP Configuration (Illustrative)
java.naming.factory.object=com.example.MaliciousClass
CVSS Analysis
The CVSS score for CVE-2025-13467 is 5.5 (Medium). This score reflects the following factors:
- Attack Vector: Network (AV:N)
- Attack Complexity: Low (AC:L)
- Privileges Required: High (PR:H) – Requires realm administrator privileges
- User Interaction: None (UI:N)
- Scope: Unchanged (S:U)
- Confidentiality Impact: Low (C:L)
- Integrity Impact: Low (I:L)
- Availability Impact: Low (A:L)
While the attack complexity is low, the requirement for administrator privileges mitigates the overall severity to medium.
Possible Impact
Successful exploitation of CVE-2025-13467 can lead to:
- Remote Code Execution (RCE): An attacker could execute arbitrary code on the Keycloak server.
- Data Exfiltration: Sensitive information stored within Keycloak, such as user credentials or configuration data, could be stolen.
- Denial of Service (DoS): The Keycloak service could be disrupted or rendered unavailable.
- Privilege Escalation: Although the attacker already requires realm administrator privileges to initiate the attack, they could potentially escalate privileges further within the system.
Mitigation and Patch Steps
The primary mitigation strategy is to apply the security patches provided by Red Hat. Refer to the following resources for detailed patching instructions:
- Apply the patches provided in RHSA-2025:22089.
- Apply the patches provided in RHSA-2025:22091.
In addition to patching, consider the following preventative measures:
- Restrict Realm Administrator Access: Limit the number of users with realm administrator privileges to the minimum necessary.
- Monitor LDAP Configurations: Regularly review and monitor LDAP server configurations for any suspicious changes.
- Harden LDAP Server: Ensure the LDAP server itself is properly secured and configured to prevent unauthorized access.
