CVE-2022-3634 is a critical vulnerability identified in the Contact Form 7 Database Addon WordPress plugin, specifically in versions prior to 1.2.6.5. This vulnerability arises due to improper neutralization of formula elements when exporting data to CSV files, classified under CWE-1236. The plugin fails to sanitize or validate user-submitted data before outputting it into CSV format. As a result, malicious actors can inject specially crafted formula expressions into CSV files generated by the plugin. When these CSV files are opened in spreadsheet applications such as Microsoft Excel or LibreOffice Calc, the embedded formulas can execute arbitrary commands or scripts, leading to potential code execution on the client side. This type of attack is commonly referred to as CSV injection or formula injection. The vulnerability has a CVSS 3.1 base score of 9.8, indicating critical severity, with an attack vector of network (AV:N), no privileges required (PR:N), no user interaction needed (UI:N), and impacts on confidentiality, integrity, and availability (C:H/I:H/A:H). Although no known exploits have been reported in the wild, the ease of exploitation combined with the high impact makes this a significant threat. The plugin is widely used in WordPress environments to store and export contact form submissions, making the attack surface potentially large. Attackers can submit malicious payloads through contact forms that get stored and later exported, triggering the vulnerability when the CSV is opened by administrators or analysts. This can lead to data theft, system compromise, or further lateral movement within the affected environment.

For European organizations, the impact of this vulnerability can be substantial. Many European businesses and public sector entities rely on WordPress for their websites and use Contact Form 7 and its associated addons for customer interaction and data collection. The CSV injection vulnerability can lead to unauthorized disclosure of sensitive data, including personal data protected under GDPR. Execution of arbitrary code on administrative machines opening the CSV files can result in full system compromise, data manipulation, or ransomware deployment. This threatens confidentiality, integrity, and availability of critical business information. Additionally, the breach of personal data can lead to regulatory fines and reputational damage. Organizations handling high volumes of customer inquiries or sensitive data via contact forms are particularly at risk. The vulnerability also poses a risk to managed service providers and web hosting companies supporting WordPress clients across Europe, potentially enabling attackers to pivot into multiple customer environments.

To mitigate this vulnerability, European organizations should immediately update the Contact Form 7 Database Addon plugin to version 1.2.6.5 or later where the issue is fixed. If immediate patching is not possible, implement input sanitization and output encoding controls to neutralize formula characters such as '=', '+', '-', '@' at the start of CSV fields. Employ CSV export filters that prepend a single quote or space to prevent formula execution in spreadsheet applications. Restrict access to exported CSV files to trusted personnel only and avoid opening CSV files from untrusted sources or in vulnerable spreadsheet software. Additionally, implement network-level protections such as web application firewalls (WAFs) to detect and block suspicious payloads submitted via contact forms. Conduct user training to raise awareness about the risks of opening untrusted CSV files. Regularly audit and monitor logs for unusual form submissions or CSV export activities. For organizations with high compliance requirements, consider disabling CSV export functionality temporarily until the patch is applied.