Vulnerability Alert CVE-2025-4665: Critical Pre-Auth SQL Injection in WordPress Contact Form Database Plugin (CFDB7)

Technical Analysis

The WordPress Contact Form CFDB7 plugin contains a critical vulnerability chain that combines SQL injection with insecure deserialization. The vulnerability exists in the bulk action processing functionality where user-controlled input flows directly into SQL queries and deserialization operations without proper validation.

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The attack requires no authentication because the vulnerable code runs in the plugin’s admin interface during bulk operations, accessible to any user who can trigger these actions.

Affected Systems

• Vulnerable Plugin: WordPress Contact Form CFDB7 Database Addon.  
• Affected Versions: All versions up to and including 1.3.2.  
• Patched Version: 1.3.3 released September 16, 2025.  

Fix Information: Version 1.3.3 addresses the vulnerability through proper SQL parameterization using $cfdb->prepare() and restricted deserialization with ['allowed_classes' => false]

Attack Chain Progression

1. Initial Request: Unauthenticated attacker accesses admin page and sends crafted requests to the CFDB7 plugin webserver.
2. SQL Injection: Attacker executes malicious SQL commands with database privileges.
3. Data Manipulation: Attacker can extract or modify database contents. 
4. Object Injection: Using SQL injection access, attackers insert malicious serialized PHP objects into database fields that trigger object injection when later deserialized by the application. 
5. Code Execution: PHP object injection enables the attacker to achieve remote code execution on the server.

Detection & Mitigation

Immediate Actions

Priority 1

• Upgrade to CFDB7 version 1.3.3 on all WordPress installations.
• Audit WordPress plugin inventories to identify vulnerable instances.
• Block CFDB7 admin endpoints at WAF level until patching is complete.

Priority 2

• Monitor database logs for unusual queries on CFDB7 tables.
• Check for new WordPress admin accounts created in the past 30 days.

Why This Matters & Lessons Learned

Scale of Exposure: CFDB7's 600,000+ installations create high exposure among the 6,700+ new vulnerabilities identified affecting the WordPress ecosystem in H1 2025. Pre-authentication access means any internet-accessible WordPress site running vulnerable versions faces exploitation without user interaction.

Attack Chain Reality: Modern web application vulnerabilities increasingly involve chained exploits where initial access through one weakness enables exploitation of additional flaws. The CFDB7 vulnerability demonstrates how SQL injection can be a stepping stone to object injection and full system compromise.

Plugin Ecosystem Risk: WordPress plugin vulnerabilities continue to be a persistent attack vector due to inconsistent security practices across the development community. Form processing plugins deserve special attention as they handle user input and often have elevated database privileges.

Runtime Detection Gaps: Runtime Detection Gaps: While static analysis tools can identify individual vulnerabilities like SQL injection and unsafe deserialization, they may miss how these flaws chain together into exploitable attack paths. Runtime analysis helps security teams understand which vulnerability combinations are actually exploitable in production environments.

Conclusion 

CFDB7’s vulnerability highlights the amplification effect of plugin vulnerabilities. Pre-authentication access combined with vulnerability chaining transforms a coding mistake into ecosystem-wide risk. WordPress security requires moving beyond individual plugin fixes to address systemic coding practices across the plugin development community.