Keycloak is an open-source identity and access management solution used by organizations worldwide to secure applications and services. It provides features such as single sign-on, identity brokering, and social login. Keycloak is employed across a range of sectors, from IT and cloud services to education and healthcare, offering a versatile means of integrating authentication services. Organizations use Keycloak to ensure secure access to various platforms, aiding in user management and data protection. The software is essential for maintaining secure and efficient user access in collaborative environments. Keycloak's role in identity management is pivotal, serving as a central piece of an organization's security apparatus.
The vulnerability in question is an unauthorized account takeover flaw identified as CVE-2026-18963. This critical vulnerability occurs within Keycloak's reset-credentials flow, allowing attackers to bypass the email verification step necessary for password resets. As a severe security breach, it enables attackers to take over user accounts by manipulating specific parameters in the password reset process. The vulnerability is particularly dangerous because it occurs even without authenticated access, making it exploitable by remote attackers. This flaw highlights weaknesses in the verification process, exposing accounts to unauthorized access and control.
The CVE-2026-18963 vulnerability specifically arises from two bugs in the Keycloak reset-credentials flow. The first bug involves the tryAnotherWay handler which incorrectly stores a generic "true" selector note without proper scoping to the execution ID. The second issue is within the ResetCredentialEmail.action() function, which calls context.success() without verifying the ACTION_TOKEN_USER_ID, allowing the bypass. The vulnerability exposes the endpoint handling reset-credentials, making it a critical point of exploitation. Attackers can leverage this flaw by chaining the bugs to reset any user's credential without triggering an email verification process. Consequently, the vulnerability facilitates an unauthorized account takeover that compromises user security.
Exploitation of this vulnerability can lead to significant security breaches within organizations using Keycloak. Malicious actors can hijack user accounts, granting them unauthorized access to sensitive information and potentially enabling further network penetration. The compromised accounts could be misused to impersonate legitimate users, leading to data theft, privilege escalation, and widespread disruption of services. Companies relying on Keycloak for user authentication may experience substantial trust issues and financial damage as a result. Protecting against such attacks requires prompt remediation to prevent additional security risks.
REFERENCES
- Upgrade Keycloak to version 26.7.2, 26.6.6, or 26.4.15 where this vulnerability has been fixed.
- As a temporary mitigation, consider disabling the "Forgot Password" feature in all realms to prevent unauthorized access attempts.
- Review and strengthen security measures and user verification processes to mitigate future vulnerabilities.
- Regularly audit user activities and maintain stringent access controls to detect and respond to unauthorized actions promptly.
- Stay informed about security patches and apply updates immediately to ensure continued protection.
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