CVE-2026-0687 identifies a missing authorization vulnerability (CWE-862) in the Meta-box GalleryMeta plugin for WordPress, affecting all versions up to and including 3.0.1. The vulnerability stems from the absence of a proper capability check on the 'mb_gallery' custom post type, which is used to manage galleries within WordPress. Authenticated users with Author-level access or higher can exploit this flaw to create and publish galleries without the necessary permissions, effectively bypassing intended access controls. This unauthorized modification capability can lead to integrity issues, such as the insertion of malicious or inappropriate content, potentially damaging the website's credibility or user trust. The CVSS v3.1 base score is 4.3 (medium severity), reflecting that the attack vector is network-based (remote), with low attack complexity, requiring privileges (Author-level), no user interaction, and impacting integrity only. No known exploits have been reported in the wild, indicating limited active exploitation at this time. The vulnerability is particularly relevant for WordPress sites that rely on the Meta-box GalleryMeta plugin and assign Author-level roles to users who may not be fully trusted or vetted. Since the plugin is widely used for managing galleries, the scope of affected systems includes any WordPress installation with this plugin active. The lack of a patch at the time of reporting necessitates immediate compensating controls to mitigate risk.

For European organizations, the primary impact of CVE-2026-0687 is the potential unauthorized modification of web content managed via the Meta-box GalleryMeta plugin. This can lead to integrity breaches where attackers with Author-level access can publish unauthorized galleries, possibly containing malicious or misleading content. While confidentiality and availability are not directly affected, the reputational damage and potential downstream effects such as phishing or malware distribution through compromised galleries can be significant. Organizations in sectors with high reliance on WordPress for content management, such as media, education, and e-commerce, are particularly at risk. The vulnerability could also be leveraged in targeted attacks to deface websites or spread misinformation. Given the ease of exploitation by any authenticated Author-level user, insider threats or compromised Author accounts pose a notable risk. The absence of known exploits in the wild reduces immediate urgency but does not eliminate the threat, especially as attackers may develop exploits over time.

To mitigate CVE-2026-0687, European organizations should implement the following specific measures: 1) Restrict the assignment of Author-level roles to trusted users only, minimizing the number of users with privileges to create or publish galleries. 2) Employ role hardening by customizing WordPress capabilities to remove or limit 'mb_gallery' post type permissions from Author roles until a patch is available. 3) Monitor and audit user activities related to gallery creation and publication to detect unauthorized actions promptly. 4) Use Web Application Firewalls (WAFs) with custom rules to detect and block suspicious requests targeting the 'mb_gallery' post type endpoints. 5) Stay informed on plugin updates from the vendor and apply patches immediately once released. 6) Consider disabling or replacing the Meta-box GalleryMeta plugin if it is not critical or if no timely patch is forthcoming. 7) Implement multi-factor authentication (MFA) for all users with Author-level or higher privileges to reduce the risk of account compromise. 8) Conduct regular security awareness training focusing on the risks associated with elevated WordPress roles and plugin vulnerabilities.