CVE-2025-12030 is an authorization bypass vulnerability classified under CWE-639 (Authorization Bypass Through User-Controlled Key) affecting the 'ACF to REST API' plugin for WordPress, versions up to and including 3.3.4. The root cause is insufficient capability checks in the update_item_permissions_check() method, which only verifies if the user has the general 'edit_posts' capability rather than object-specific permissions like edit_post($id), edit_user($id), or manage_options. This flaw allows authenticated users with Contributor-level access or higher to modify Advanced Custom Fields (ACF) data on posts they do not own, other user accounts, comments, taxonomy terms, and even the global options page via the REST API endpoints structured as /wp-json/acf/v3/{type}/{id}. Because the check does not validate ownership or specific permissions on the targeted object, attackers can escalate their privileges within the scope of the plugin's REST API functionality. The vulnerability requires authentication but no additional user interaction, and it does not expose confidential data directly but allows unauthorized modification of site content and configuration, potentially leading to site defacement, misinformation, or configuration tampering. No public exploits have been reported yet, and no patches are linked at this time, indicating the need for vigilance and proactive mitigation. The CVSS v3.1 score is 4.3 (medium), reflecting the limited scope of impact (integrity only), the requirement for authenticated access, and the lack of impact on confidentiality or availability.

For European organizations, this vulnerability poses a risk primarily to the integrity of WordPress-based websites that utilize the ACF to REST API plugin. Attackers with Contributor-level access can modify content fields, user accounts, comments, taxonomy terms, and global options without proper authorization, potentially leading to unauthorized content changes, privilege escalation, or site misconfiguration. This can damage brand reputation, mislead users, or disrupt normal site operations. Organizations relying on WordPress for public-facing or internal content management are particularly vulnerable if they allow contributors or editors to authenticate. The impact is heightened for entities with strict content governance or regulatory compliance requirements, as unauthorized modifications could violate data integrity policies. Although no known exploits are currently active, the vulnerability's presence in widely used WordPress plugins means that targeted attacks could emerge, especially against high-profile European websites. The medium severity score suggests moderate risk but warrants prompt attention to prevent exploitation.

1. Monitor official channels for patches or updates from the plugin vendor and apply them immediately once available. 2. Until patches are released, restrict Contributor and Editor roles from accessing or modifying ACF fields via the REST API by implementing custom permission filters or disabling the REST endpoints related to ACF where feasible. 3. Employ a Web Application Firewall (WAF) with rules to detect and block suspicious REST API requests targeting /wp-json/acf/v3/ endpoints. 4. Audit user roles and permissions to ensure that only trusted users have Contributor-level access or higher. 5. Implement logging and monitoring of REST API activity to detect unauthorized modification attempts. 6. Consider temporarily disabling the ACF to REST API plugin if it is not essential to reduce attack surface. 7. Harden WordPress security by enforcing strong authentication mechanisms and limiting plugin installations to trusted sources. 8. Educate site administrators and content contributors about the risks of unauthorized REST API access and the importance of role-based access control.