CVE-2026-0871 identifies an incorrect privilege assignment vulnerability in the Red Hat build of Keycloak version 26.4. Keycloak is an open-source identity and access management solution widely used for authentication and authorization. The vulnerability specifically involves the 'manage-users' permission granted to administrators. Normally, the system setting 'Only administrators can view' unmanaged attributes is designed to restrict access and modification of certain user profile attributes to only authorized administrators. However, due to improper access control implementation, an administrator with 'manage-users' permission can bypass this setting and modify unmanaged attributes that should be protected. This flaw does not allow unauthorized users or lower-privileged roles to exploit it; it requires administrative privileges. The vulnerability impacts the integrity of user profile data, as unauthorized changes can be made despite configuration settings intended to prevent such modifications. The CVSS 3.1 vector (AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N) indicates network exploitability with low attack complexity, requiring high privileges but no user interaction, affecting integrity but not confidentiality or availability. There are no known exploits in the wild at this time, and no patches or fixes were explicitly linked in the provided data, though Red Hat typically issues updates promptly. This vulnerability highlights the importance of strict privilege management and access control enforcement within identity management platforms.

The primary impact of CVE-2026-0871 is the unauthorized modification of user profile attributes by administrators who possess the 'manage-users' permission but should not have access to certain unmanaged attributes. This can lead to integrity violations where user data is altered without proper authorization, potentially causing issues such as incorrect user roles, privileges, or identity information. In environments where user attributes control access to sensitive resources or compliance requirements depend on accurate user data, this vulnerability could facilitate privilege escalation, unauthorized access, or audit failures. Although confidentiality and availability are not directly affected, the integrity compromise can undermine trust in the identity management system and complicate incident response. Organizations relying on Red Hat Keycloak 26.4 for centralized user management, especially in regulated industries like finance, healthcare, and government, may face increased risk of insider threats or administrative misuse. The requirement for administrative privileges limits the attack surface but does not eliminate risk, as malicious or compromised administrators could exploit this flaw. The absence of known exploits reduces immediate risk but does not preclude future exploitation attempts.

To mitigate CVE-2026-0871, organizations should first verify if they are running Red Hat build of Keycloak version 26.4 and prioritize updating to a patched version once available from Red Hat. In the absence of an immediate patch, implement strict role-based access control (RBAC) policies to minimize the number of administrators granted the 'manage-users' permission. Segregate duties so that no single administrator has excessive privileges that could be abused. Audit and monitor administrative actions related to user attribute modifications to detect anomalous behavior promptly. Review and harden Keycloak configuration settings to ensure that unmanaged attributes are protected as intended, possibly by disabling or restricting their use if feasible. Employ multi-factor authentication (MFA) for all administrative accounts to reduce the risk of credential compromise. Additionally, conduct regular security assessments and penetration testing focused on privilege escalation and access control weaknesses within the identity management infrastructure. Maintain comprehensive logging and alerting on changes to user profiles to facilitate rapid incident response if exploitation occurs.