The ShortPixel Image Optimizer plugin for WordPress, widely used for image optimization and conversion to WebP and AVIF formats, contains a vulnerability identified as CVE-2025-11378. This vulnerability is classified under CWE-862 (Missing Authorization) and affects all versions up to and including 6.3.4. The root cause is a missing capability check on the 'shortpixel_ajaxRequest' AJAX action, which is responsible for handling certain plugin operations. Because of this missing authorization, any authenticated user with at least Contributor-level privileges can exploit this flaw to export and import site options, effectively modifying site configurations without proper permission. The vulnerability does not require user interaction beyond authentication, and the attack vector is network-based (remote). The CVSS v3.1 score is 5.4 (medium), reflecting that the attack requires low complexity and privileges but impacts only confidentiality and integrity, not availability. No public exploits are known at this time, but the vulnerability poses a risk in environments where Contributor roles are assigned to users who should not have such capabilities. The plugin's widespread use in WordPress installations makes this a relevant concern for many websites, especially those with multiple contributors or less stringent role management policies.

For European organizations, the vulnerability can lead to unauthorized modification of site options, potentially exposing sensitive configuration data or enabling further malicious changes to the website's behavior. This can undermine the integrity and confidentiality of the affected WordPress sites, possibly leading to data leakage or unauthorized site manipulation. Organizations relying on ShortPixel for image optimization may face reputational damage if attackers leverage this flaw to alter site content or configurations. The impact is particularly significant for entities with multiple contributors or external collaborators who have Contributor-level access, as these users could exploit the vulnerability to escalate their influence over the site. While availability is not directly affected, the indirect consequences of unauthorized configuration changes could disrupt normal operations or security postures. Given the widespread use of WordPress across Europe, especially in sectors like e-commerce, media, and public services, the vulnerability represents a moderate risk that requires timely mitigation.

1. Monitor the ShortPixel plugin's official channels for a security patch addressing CVE-2025-11378 and apply updates immediately upon release. 2. Until a patch is available, restrict Contributor-level permissions by reviewing and tightening user roles and capabilities in WordPress, ensuring that only trusted users have such access. 3. Implement web application firewall (WAF) rules to detect and block suspicious AJAX requests targeting 'shortpixel_ajaxRequest' actions from unauthorized users. 4. Audit existing site options export/import logs and configurations for any unauthorized changes to detect potential exploitation. 5. Consider temporarily disabling the ShortPixel plugin if Contributor-level access cannot be sufficiently controlled or monitored. 6. Educate site administrators and contributors about the risk and encourage strong authentication practices to reduce the risk of compromised accounts. 7. Employ security plugins that can enforce granular capability checks and monitor AJAX actions for anomalous behavior.