CVE-2026-104010: WPSyncSheets For Contact Form 7 <= 1.8.0 - Unauthenticated PHP Object Injection to Remote Code Execution via Untrusted CF7 Submission Field via maybe_unserialize()
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 allowedclasses restriction on maybeunserialize() 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.
Event History
Frequently Asked Questions
What conditions are required for remote code execution?
An attacker can submit a crafted value in any non-system Contact Form 7 field, such as a message field, without authentication. Remote code execution additionally requires that a Google Sheets access token is configured in the plugin, because this causes the bundled Monolog 2.10.0 classes needed for the gadget chain to be loaded.
Are sites without a configured Google Sheets access token affected?
The underlying PHP object injection can still occur without a Google Sheets access token. However, the described remote code execution gadget chain depends on the token configuration and its resulting autoloading of the bundled Monolog library.
Which input paths should be considered exposed?
Any non-system Contact Form 7 submission field is an affected input path. Publicly reachable Contact Form 7 forms using those fields can therefore accept the untrusted values used in the attack.