CVE-2018-9035 in Contact Form 7 to Database Extension Plugin
Summary
by MITRE
CSV Injection vulnerability in ExportToCsvUtf8.php of the Contact Form 7 to Database Extension plugin 2.10.32 for WordPress allows remote attackers to inject spreadsheet formulas into CSV files via the contact form.
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Analysis
by VulDB Data Team • 08/16/2025
The CSV Injection vulnerability identified as CVE-2018-9035 affects the Contact Form 7 to Database Extension plugin version 2.10.32 for WordPress systems. This vulnerability resides within the ExportToCsvUtf8.php file and represents a critical security flaw that enables remote attackers to execute malicious spreadsheet formulas through contact form submissions. The vulnerability stems from insufficient input validation and sanitization of user-supplied data that gets exported to CSV format, creating a pathway for formula injection attacks that can compromise spreadsheet applications when the exported files are opened.
The technical flaw manifests when user input from contact forms is directly incorporated into CSV export files without proper sanitization of potentially malicious content. Attackers can exploit this by submitting spreadsheet formula strings beginning with special characters like equals sign, plus, minus, or @ symbols that are interpreted by spreadsheet applications like Microsoft Excel, Google Sheets, or LibreOffice Calc. When these malicious formulas are opened in spreadsheet applications, they can execute unintended commands including file system operations, network requests, or data exfiltration, making this a particularly dangerous vulnerability for organizations that rely on spreadsheet processing of contact form data.
The operational impact of this vulnerability extends beyond simple data corruption, as it can lead to significant security breaches and system compromise. When victims open the compromised CSV files in spreadsheet applications, the injected formulas can trigger automatic execution of malicious code, potentially leading to unauthorized data access, system command execution, or even full system compromise depending on the spreadsheet application's handling of the injected formulas. This vulnerability particularly affects organizations that process contact form submissions through WordPress platforms and subsequently analyze the data in spreadsheet applications, creating a direct attack surface between web applications and office productivity tools.
Security professionals should implement multiple layers of mitigation for this vulnerability, beginning with immediate plugin updates to versions that address the CSV injection flaw. Organizations should also consider implementing input validation at multiple levels including application-level sanitization of exported data, implementing Content Security Policies that restrict formula execution in spreadsheet applications, and establishing network segmentation to limit access to affected systems. The vulnerability aligns with CWE-1236 which addresses the improper neutralization of special elements used in spreadsheet formulas, and maps to ATT&CK technique T1059.005 for command and scripting interpreter execution through spreadsheet applications. Additionally, organizations should conduct regular security assessments of their WordPress plugins and implement automated monitoring for similar vulnerabilities in third-party components to prevent future incidents of this nature.