CVE-2025-14778 identifies a Broken Access Control vulnerability in the Red Hat build of Keycloak version 26.2, specifically within the UserManagedPermissionService (UMA Protection API). The UMA API allows users to create and manage authorization policies for resources. The vulnerability arises when a UMA policy is associated with multiple resources owned by different users. When a user attempts to update or delete such a policy, the authorization check only verifies ownership against the first resource in the policy's resource list. Consequently, a user who owns one resource (Owner A) can update or delete a shared policy and inadvertently or maliciously modify authorization rules for other resources (e.g., RB) owned by different users (Owner B). This flaw constitutes a horizontal privilege escalation, as it allows users to affect access controls beyond their legitimate scope. The vulnerability is exploitable remotely over the network with low attack complexity, requires the attacker to have some privileges (PR:L), and does not require user interaction. The impact includes unauthorized modification of access policies, potentially leading to unauthorized access or denial of access for other users. Although no known exploits are reported in the wild, the flaw poses a significant risk in multi-tenant or collaborative environments where UMA policies are shared across resources. The vulnerability has been assigned a CVSS v3.1 base score of 5.4, reflecting a medium severity level due to limited confidentiality and integrity impact and no impact on availability.

The primary impact of CVE-2025-14778 is unauthorized horizontal privilege escalation within environments using Red Hat's Keycloak 26.2. Attackers who legitimately own one resource can manipulate UMA policies affecting other users' resources, potentially granting themselves or others unauthorized access or revoking legitimate access. This undermines the integrity of access control mechanisms and can lead to data exposure, unauthorized actions, or disruption of service for affected users. Organizations relying on Keycloak for identity and access management, especially those with shared or multi-tenant resource policies, face risks of unauthorized privilege modifications that could compromise sensitive data or critical operations. While the vulnerability does not directly impact availability, the integrity and confidentiality risks are significant in environments with complex resource sharing. The medium CVSS score reflects that exploitation requires some privileges but can be performed remotely without user interaction, increasing the threat surface. The lack of known exploits in the wild suggests the vulnerability is not yet actively exploited, but the potential for abuse remains high if unmitigated.

To mitigate CVE-2025-14778, organizations should apply any available patches or updates from Red Hat for Keycloak 26.2 as soon as they are released. In the absence of patches, administrators should audit UMA policies that are associated with multiple resources and restrict policy sharing to minimize cross-resource ownership scenarios. Implement strict monitoring and alerting on changes to UMA policies, especially those affecting multiple resources, to detect unauthorized modifications promptly. Review and tighten user privileges to limit who can create or modify UMA policies, ensuring only trusted users have such capabilities. Consider segmenting resources and policies to reduce the risk of horizontal privilege escalation by isolating resource ownership domains. Additionally, conduct regular access reviews and penetration testing focused on UMA policy management to identify and remediate potential abuse paths. Finally, maintain comprehensive logging of authorization checks and policy changes for forensic analysis if exploitation is suspected.