CVE-2025-8420: WordPress emarket-design Plugin RCE Flaw

CVE-2025-8420 Overview

Multiple WordPress plugins developed by emarket-design that incorporate the emd-form-builder-lite package are vulnerable to Remote Code Execution (RCE). The vulnerability exists in the emd_form_builder_lite_pagenum function, which fails to properly validate user input before using it as a function name. This improper validation allows unauthenticated attackers to execute arbitrary code on the server, although the exploit is limited in that parameters cannot be passed to the called functions.

Critical Impact

Unauthenticated attackers can achieve remote code execution on WordPress sites running vulnerable emarket-design plugins, potentially leading to complete server compromise, data theft, or malware distribution.

Affected Products

• WordPress plugins by emarket-design using emd-form-builder-lite package
• Request a Quote plugin
• Software Issue Manager plugin
• WP Ticket plugin
• WP Easy Events plugin
• YouTube Showcase plugin

Discovery Timeline

• 2025-08-06 - CVE-2025-8420 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-8420

Vulnerability Analysis

This vulnerability is classified as CWE-95 (Improper Neutralization of Directives in Dynamically Evaluated Code), commonly referred to as "Eval Injection." The emd_form_builder_lite_pagenum function within the emd-form-builder-lite package accepts user-supplied input and directly uses it as a function name without proper sanitization or validation. This design flaw enables attackers to invoke arbitrary PHP functions available in the server environment.

The attack requires no authentication, making it particularly dangerous for internet-facing WordPress installations. While the exploit is constrained by the inability to pass parameters to the invoked functions, this limitation does not prevent attackers from calling parameterless functions that could still cause significant harm, such as functions that disclose sensitive information or modify server state.

Root Cause

The root cause of this vulnerability lies in improper input validation within the emd_form_builder_lite_pagenum function. The plugin developers failed to implement a whitelist of allowed function names or proper sanitization of user-supplied input before using it in a dynamic function call context. This violates secure coding principles that mandate strict validation of any user input that influences code execution flow.

Attack Vector

The vulnerability is exploitable over the network without requiring authentication. An attacker can craft malicious HTTP requests targeting the vulnerable function endpoint in WordPress. By manipulating the input parameter that gets processed by emd_form_builder_lite_pagenum, the attacker can specify the name of a PHP function to execute on the server.

The attack complexity is considered high because successful exploitation may require specific knowledge of available functions in the server environment and the exact request format needed to trigger the vulnerable code path. However, once these requirements are understood, the attack can be automated and executed against any vulnerable WordPress installation.

Detection Methods for CVE-2025-8420

Indicators of Compromise

• Unusual HTTP requests containing PHP function names in POST or GET parameters targeting emarket-design plugin endpoints
• Web server logs showing requests to form builder AJAX handlers with suspicious payloads
• Unexpected PHP error messages in logs indicating attempts to call non-existent or restricted functions
• Evidence of unauthorized code execution such as new files created, modified configurations, or unexpected processes

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block requests containing PHP function names in unexpected parameters
• Monitor WordPress AJAX endpoints for anomalous request patterns, particularly those targeting emd_form_builder_lite handlers
• Deploy file integrity monitoring to detect unauthorized changes to WordPress core, plugin, or theme files
• Review web server access logs for suspicious request patterns targeting known vulnerable plugin paths

Monitoring Recommendations

• Enable verbose logging for WordPress AJAX requests and review logs regularly for exploitation attempts
• Configure security information and event management (SIEM) rules to alert on patterns indicative of RCE attempts
• Monitor server processes for unexpected PHP executions or spawned child processes
• Implement real-time alerting for any changes to critical WordPress files or database tables

How to Mitigate CVE-2025-8420

Immediate Actions Required

• Update all affected emarket-design plugins to the latest patched versions immediately
• Audit WordPress installations to identify all plugins using the emd-form-builder-lite package
• If updates are not immediately available, consider temporarily disabling the affected plugins
• Review web server logs for signs of prior exploitation and conduct incident response if compromise is detected

Patch Information

Security patches have been released through the WordPress plugin repository. Multiple changesets address this vulnerability across the affected plugins:

• WordPress Plugin Changeset 3346435
• WordPress Plugin Changeset 3346460
• WordPress Plugin Changeset 3347084

Additional updates are available for specific plugins including Request a Quote, Software Issue Manager, WP Ticket, WP Easy Events, and YouTube Showcase. For detailed vulnerability analysis, refer to the Wordfence Vulnerability Analysis.

Workarounds

• Implement a Web Application Firewall with rules to block requests containing potential function name injection patterns
• Restrict access to WordPress admin and AJAX endpoints using IP-based access controls where feasible
• Deploy server-level PHP security configurations such as disable_functions to limit available PHP functions
• Consider placing vulnerable sites behind a reverse proxy with request inspection capabilities until patches can be applied

# Example WAF rule concept for ModSecurity
# Block requests containing PHP function names in form builder parameters
SecRule ARGS "@rx ^[a-z_]+$" "id:100001,phase:2,deny,status:403,msg:'Potential RCE attempt in emd-form-builder',chain"
SecRule REQUEST_URI "@contains emd_form_builder"