CVE-2025-14351 is a vulnerability classified under CWE-862 (Missing Authorization) found in the WordPress plugin 'Custom Fonts – Host Your Fonts Locally' developed by Brainstormforce. The flaw exists in the constructor function of the BCF_Google_Fonts_Compatibility class, where a critical capability check is missing. This omission allows unauthenticated attackers to perform unauthorized operations, specifically deleting the font directory and rewriting the theme.json file. The plugin is widely used to host custom fonts locally on WordPress sites, enhancing performance and privacy by avoiding external font calls. The vulnerability affects all plugin versions up to 2.1.16, with no authentication or user interaction required, making it remotely exploitable over the network. The impact primarily concerns integrity, as attackers can alter or remove font files and modify theme configuration, potentially causing website display issues or defacement. The CVSS 3.1 base score is 5.3 (medium), reflecting network attack vector, low complexity, no privileges required, and no user interaction needed. No known public exploits have been reported yet, but the vulnerability's nature suggests it could be leveraged for website disruption or as part of a broader attack chain. The lack of a patch at the time of reporting increases the urgency for mitigation through alternative controls.

For European organizations, the vulnerability poses a risk to the integrity of WordPress-based websites using the affected plugin. Unauthorized deletion of font directories and modification of theme.json can lead to website defacement, broken layouts, or degraded user experience, potentially damaging brand reputation and customer trust. E-commerce platforms, media outlets, and public sector websites relying on custom fonts for branding are particularly vulnerable. While confidentiality and availability impacts are minimal, the integrity compromise could facilitate further attacks, such as injecting malicious content or disrupting site operations. The ease of exploitation without authentication increases the threat level, especially for organizations with publicly accessible WordPress sites. Given the widespread use of WordPress in Europe, the vulnerability could affect a significant number of sites, leading to potential operational disruptions and increased incident response costs.

Until an official patch is released, European organizations should implement the following specific mitigations: 1) Restrict file system permissions for the WordPress installation, especially the font directories and theme.json file, to prevent unauthorized write or delete operations by the web server user. 2) Employ web application firewalls (WAFs) with custom rules to detect and block suspicious requests targeting the plugin's endpoints or actions related to font management. 3) Monitor file integrity using tools like WordPress file monitoring plugins or external solutions to detect unauthorized changes promptly. 4) Disable or remove the 'Custom Fonts – Host Your Fonts Locally' plugin if it is not essential, or replace it with alternative plugins that have verified secure authorization checks. 5) Keep WordPress core and all plugins updated and subscribe to vulnerability advisories for timely patch application. 6) Conduct regular security audits focusing on plugin permissions and access controls to ensure no unauthorized modifications are possible. These steps go beyond generic advice by focusing on access control hardening and proactive monitoring tailored to the specific vulnerability.