CVE-2025-6838 is a medium-severity vulnerability classified under CWE-1236, which pertains to improper neutralization of formula elements in CSV files. This vulnerability affects the Broken Link Notifier plugin for WordPress, developed by apos37, in all versions up to and including 1.3.0. The flaw arises because the plugin does not properly sanitize or neutralize untrusted input embedded in broken link data before exporting it into CSV files. An authenticated attacker with Contributor-level access or higher can exploit this by injecting malicious formula elements into the broken links data. When these CSV files are subsequently downloaded and opened on a local system using spreadsheet software that evaluates formulas (such as Microsoft Excel), the malicious formulas can execute arbitrary code or commands. This can lead to code execution on the client machine, potentially compromising the user's system. The vulnerability requires authentication and user interaction (opening the CSV file), and the attack vector is network-based with low attack complexity. The CVSS v3.1 base score is 4.1, reflecting a medium severity primarily due to the limited scope and requirement for user action. No known exploits are currently reported in the wild. The vulnerability highlights the risk of CSV Injection attacks in web applications that export user-controllable data to CSV format without proper sanitization or escaping of formula characters such as '=', '+', '-', or '@'.

For European organizations using WordPress sites with the Broken Link Notifier plugin, this vulnerability poses a risk primarily to users who download and open exported CSV reports containing broken link data. The impact is mainly on the integrity and confidentiality of the local systems where the CSV files are opened, as malicious formulas can execute arbitrary commands or scripts. This could lead to local system compromise, data theft, or lateral movement within the organization's network if the compromised user has elevated privileges. Since the vulnerability requires authenticated access at Contributor level or above, it is particularly concerning for organizations with multiple content contributors or editors. The risk is amplified in environments where users are less aware of CSV Injection risks or where endpoint protections do not adequately detect malicious spreadsheet content. While the vulnerability does not directly affect the availability of the WordPress site, the potential for client-side compromise can lead to broader security incidents. European organizations with compliance requirements around data integrity and endpoint security should consider this vulnerability a moderate threat that requires timely mitigation to prevent exploitation.

To mitigate this vulnerability, European organizations should take the following specific actions: 1) Immediately update the Broken Link Notifier plugin to a patched version once released by the vendor. In the absence of a patch, consider disabling the CSV export functionality or the plugin entirely to prevent exploitation. 2) Implement strict role-based access controls on WordPress sites to limit Contributor-level or higher access only to trusted users, reducing the risk of malicious input injection. 3) Educate users and administrators about the risks of CSV Injection and advise caution when opening CSV files from untrusted or internal sources, especially those exported from the Broken Link Notifier plugin. 4) Employ endpoint security solutions capable of detecting and blocking malicious macro or formula execution in spreadsheet applications. 5) As a technical workaround, sanitize or escape formula characters ('=', '+', '-', '@') in broken link data before exporting to CSV, either by modifying the plugin code or using a filtering proxy. 6) Monitor logs and user activities for unusual CSV export or download patterns that could indicate exploitation attempts. 7) Regularly audit WordPress user roles and plugin versions to ensure compliance with security best practices.