CVE-2025-4665 in Contact Form 7 Database Addon CFDB7 Plugin
Summary
by MITRE • 10/29/2025
WordPress plugin Contact Form CFDB7 versions up to and including 1.3.2 are affected by a pre-authentication SQL injection vulnerability that cascades into insecure deserialization (PHP Object Injection). The weakness arises due to insufficient validation of user input in plugin endpoints, allowing crafted input to influence backend queries in unexpected ways. Using specially crafted payloads, this can escalate into unsafe deserialization, enabling arbitrary object injection in PHP. Although the issue is remotely exploitable without authentication, it does require a crafted interaction with the affected endpoint in order to trigger successfully.
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Analysis
by VulDB Data Team • 10/30/2025
The vulnerability identified as CVE-2025-4665 affects the Contact Form CFDB7 WordPress plugin, specifically versions 1.3.2 and earlier, presenting a critical security risk that combines multiple exploitation vectors. This issue stems from inadequate input validation mechanisms within the plugin's backend endpoints, creating a pathway for attackers to manipulate database queries through carefully crafted payloads. The vulnerability operates at the intersection of two significant security weaknesses, creating a cascading effect that amplifies its potential impact. The plugin's failure to properly sanitize user-provided data in its API endpoints creates an environment where malicious actors can inject SQL commands directly into the database layer, bypassing normal authentication mechanisms and gaining unauthorized access to backend systems.
The technical exploitation of this vulnerability follows a multi-stage attack pattern that begins with SQL injection and transitions into PHP object injection. The initial SQL injection occurs when user input flows directly into database queries without proper sanitization or parameterization, allowing attackers to manipulate the intended query execution path. This vulnerability maps to CWE-89, which specifically addresses SQL injection flaws, and CWE-502, which covers insecure deserialization issues. The attack chain continues when the manipulated SQL data is subsequently processed through PHP's serialization mechanisms, creating opportunities for object injection attacks that can execute arbitrary code on the target system. The attack requires only a single interaction with the vulnerable endpoint, making it particularly dangerous as it can be exploited remotely without prior authentication, aligning with ATT&CK technique T1213.002 for data from information repositories and T1071.004 for application layer protocols.
The operational impact of this vulnerability extends beyond simple data theft or manipulation, as it provides attackers with a potential foothold for further compromise within the WordPress environment. Successful exploitation could enable attackers to extract sensitive information from the database, modify contact form configurations, or even escalate privileges within the WordPress installation. The insecure deserialization component particularly threatens system integrity, as PHP object injection attacks can potentially execute arbitrary code with the privileges of the web server process. The vulnerability's remote exploitability without authentication means that any user with access to the WordPress site can potentially trigger the attack, making it a significant threat to all installations running vulnerable plugin versions. This weakness also aligns with ATT&CK tactic TA0006 (credential access) and TA0005 (defense evasion) as attackers can leverage the vulnerability to maintain persistent access and avoid detection mechanisms.
Organizations affected by this vulnerability should immediately implement mitigations including updating to the patched version of the Contact Form CFDB7 plugin, implementing web application firewalls to monitor and block suspicious requests, and conducting thorough security assessments of their WordPress installations. The recommended remediation strategy involves not only patching the specific vulnerability but also implementing input validation controls at multiple layers of the application architecture. Security teams should also consider implementing database query logging and monitoring to detect anomalous SQL patterns that may indicate exploitation attempts. Additional protective measures include restricting access to plugin endpoints, implementing rate limiting for API calls, and conducting regular security audits of third-party WordPress plugins to identify similar vulnerabilities. The incident response plan should include monitoring for signs of exploitation such as unusual database activity, unauthorized configuration changes, or unexpected file modifications that might indicate successful object injection attacks.