Description

The WPSyncSheets For Contact Form 7 – CF7 Google Sheets Connector & Save to Database plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, 1.8.0 via the 'any non-system CF7 field (e.g., your-message)' parameter parameter. This is due to insufficient sanitization of CF7 submission field values before database storage and the absence of an allowed_classes restriction on maybe_unserialize() during admin retrieval. This makes it possible for unauthenticated attackers to execute code on the server. Successful exploitation of the remote code execution gadget chain requires that a Google Sheets access token be configured in the plugin (its primary advertised feature), as this triggers autoloading of the bundled Monolog 2.10.0 library whose classes form the exploitable gadget chain; however, the underlying PHP Object Injection occurs regardless.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.5",
  "pubDate": "2026-11-06T12:17:15.827Z",
  "pubdate": "2026-11-06T12:17:15.827Z",
  "executiveSummary": "The WPSyncSheets For Contact Form 7 – CF7 Google Sheets Connector & Save to Database plugin is susceptible to Remote Code Execution (RCE) via PHP Object Injection.\nThis vulnerability affects all versions up to and including 1.8.0.\nThe flaw stems from insufficient input sanitization of user-supplied Contact Form 7 (CF7) fields, which are subsequently processed through an insecure deserialization operation.\nSuccessful exploitation allows unauthenticated attackers to execute arbitrary code on the underlying host server.\nThe vulnerability is primarily enabled by the absence of class allow-listing during the retrieval of stored form data, coupled with the presence of a gadget chain within the bundled Monolog 2.10.0 library.\nExecution of the RCE gadget chain is contingent upon the plugin having a Google Sheets access token configured, as this configuration state triggers the autoloading of the vulnerable library.\nGiven the ability to execute code, the risk is classified as critical, providing attackers full control over the WordPress environment.",
  "technicalDetails": "The root cause of this vulnerability is a combination of insecure data storage and insecure deserialization within the WPSyncSheets For Contact Form 7 – CF7 Google Sheets Connector plugin.\nDuring the submission process, the plugin accepts arbitrary CF7 field values (e.g., 'your-message') and stores them into the database without adequate sanitization or structural validation.\nThe critical flaw manifests during the admin-side retrieval of these records, where the plugin utilizes the 'maybe_unserialize()' function on the stored data. Because this function is invoked without an 'allowed_classes' restriction, it permits the instantiation of arbitrary PHP classes that are currently defined within the application's scope.\nThe attack flow begins with an unauthenticated attacker injecting a serialized PHP object into a CF7 field. When the form is submitted, the malicious payload is stored in the database.\nWhen a plugin administrator subsequently views the submissions, the application retrieves the serialized string and passes it to 'maybe_unserialize()'.\nExploitation relies on the presence of a gadget chain—a sequence of class methods that, when triggered by object destruction or method invocation during deserialization, perform unintended actions. In this specific scenario, the required gadgets are available within the Monolog 2.10.0 library, which is bundled with the plugin.\nThe exploit process is conditional: the Monolog library is only loaded if the plugin's Google Sheets integration is active (requiring a configured access token). If the integration is active, the application autoloader makes the gadget chain classes available for the deserialization process to utilize.\nBy crafting a serialized payload targeting these specific Monolog classes, an attacker can achieve Remote Code Execution.\nThe impact of this vulnerability is total system compromise. Once arbitrary code execution is achieved, an attacker can bypass authentication, modify system files, access the database, or pivot to other areas of the server environment. This vulnerability exposes the application to data exfiltration, service disruption, and the deployment of persistent backdoors."
}