CVE-2025-15476 is a vulnerability identified in the WordPress plugin The Bucketlister, developed by simonfairbairn, affecting all versions up to and including 0.1.5. The root cause is a missing authorization check (CWE-862) in the bucketlister_do_admin_ajax() function, which handles AJAX requests for administrative actions within the plugin. This flaw allows any authenticated user with at least Subscriber-level privileges to perform unauthorized modifications to bucket list items, including adding, deleting, or altering entries. The vulnerability arises because the function does not verify whether the user has sufficient capabilities to perform these actions, effectively bypassing intended access controls. The CVSS v3.1 score is 4.3 (medium severity), reflecting that the attack vector is network-based, requires low complexity, and privileges at the level of a logged-in user, but does not affect confidentiality or availability. No user interaction is required beyond authentication. Although no known exploits have been reported in the wild, the vulnerability poses a risk to the integrity of data managed by the plugin. Since The Bucketlister is a WordPress plugin, the vulnerability impacts websites using this plugin, potentially allowing attackers to manipulate content or data presented to end users or administrators. The lack of an available patch at the time of publication means that mitigation relies on access control and monitoring.

For European organizations, the primary impact of CVE-2025-15476 is the unauthorized modification of bucket list data on WordPress sites using The Bucketlister plugin. While this does not directly compromise sensitive data confidentiality or site availability, it undermines data integrity and could lead to misinformation or manipulation of user-facing content. Organizations relying on this plugin for customer engagement, marketing, or internal tracking may face reputational damage if attackers alter displayed information. Additionally, attackers with Subscriber-level access could leverage this vulnerability as a foothold for further attacks or privilege escalation if combined with other vulnerabilities. The impact is more pronounced for organizations with public-facing WordPress sites that allow user registration or have multiple authenticated users with low privileges. Given the medium severity and absence of known exploits, the immediate risk is moderate, but the potential for misuse exists, especially in sectors where data integrity is critical, such as media, education, or tourism. European entities with compliance requirements around data integrity and website security should consider this vulnerability a priority for remediation.

Since no official patch is currently available, European organizations should implement several practical mitigations: 1) Restrict WordPress user roles and capabilities to the minimum necessary, ensuring that Subscriber-level users cannot access or trigger administrative AJAX functions related to The Bucketlister plugin. 2) Employ Web Application Firewalls (WAFs) with custom rules to detect and block suspicious AJAX requests targeting bucketlister_do_admin_ajax(). 3) Monitor WordPress logs and plugin activity for unusual modifications to bucket list items, enabling early detection of exploitation attempts. 4) Disable or uninstall The Bucketlister plugin if it is not essential to reduce attack surface. 5) Regularly audit user accounts and remove inactive or unnecessary Subscriber-level users to limit potential attackers. 6) Stay informed on updates from the plugin developer or WordPress security advisories to apply patches promptly once released. 7) Consider isolating WordPress installations with this plugin behind additional authentication layers or VPNs to restrict access to trusted users only. These targeted steps go beyond generic advice by focusing on access control, monitoring, and proactive user management tailored to this vulnerability's characteristics.