CVE-2025-49029: Custom Login Widget Code Injection Flaw

CVE-2025-49029 Overview

CVE-2025-49029 is a Code Injection vulnerability (CWE-94) affecting the Custom Login And Signup Widget plugin for WordPress, developed by bitto.kazi. This vulnerability allows attackers to inject and execute arbitrary code within the context of the affected WordPress installation, potentially leading to complete site compromise.

The Improper Control of Generation of Code vulnerability exists in the plugin's handling of user-supplied input, enabling malicious actors to execute arbitrary code on vulnerable WordPress sites. This type of vulnerability is particularly dangerous in WordPress environments where successful exploitation can lead to unauthorized administrative access, data theft, or use of the compromised site for further attacks.

Critical Impact

Arbitrary code execution vulnerability in a WordPress authentication plugin could allow attackers to bypass login controls and gain unauthorized access to WordPress installations.

Affected Products

• Custom Login And Signup Widget plugin version 1.0 and earlier
• WordPress installations using the affected plugin versions

Discovery Timeline

• 2025-07-01 - CVE-2025-49029 published to NVD
• 2026-04-01 - Last updated in NVD database

Technical Details for CVE-2025-49029

Vulnerability Analysis

This vulnerability falls under CWE-94 (Improper Control of Generation of Code), commonly known as Code Injection. The Custom Login And Signup Widget plugin fails to properly sanitize or validate user-supplied input before incorporating it into dynamically generated code. This fundamental security flaw allows attackers to craft malicious input that, when processed by the plugin, results in the execution of arbitrary code on the server.

In WordPress plugin contexts, code injection vulnerabilities typically arise when plugins use functions like eval(), create_function(), or similar constructs that interpret strings as executable code without proper input validation. The authentication-related nature of this plugin makes exploitation particularly concerning, as it handles sensitive user data and access control functions.

Root Cause

The root cause of CVE-2025-49029 stems from improper input validation within the Custom Login And Signup Widget plugin. The plugin does not adequately sanitize user-controlled data before using it in code generation contexts. This allows specially crafted input to escape its intended context and be interpreted as executable PHP code by the WordPress/PHP runtime environment.

Attack Vector

The attack vector for this vulnerability involves submitting malicious input through the plugin's login or signup functionality. An attacker can craft a request containing code injection payloads that exploit the lack of input sanitization. When the vulnerable code path processes this input, the injected code executes with the privileges of the WordPress/PHP process.

The vulnerability can be exploited remotely without authentication, as it affects the login and signup functionality—features designed to be publicly accessible. Successful exploitation could allow an attacker to:

• Execute arbitrary PHP code on the server
• Read or modify WordPress database contents
• Create administrative user accounts
• Install backdoors or malware
• Pivot to attack other applications on the same server

For detailed technical analysis, refer to the Patchstack Vulnerability Report.

Detection Methods for CVE-2025-49029

Indicators of Compromise

• Unexpected PHP files created in WordPress directories, particularly in wp-content/plugins/custom-login-and-signup-widget/
• Unusual database entries indicating unauthorized admin user creation
• Web server logs showing malformed POST requests to login or signup endpoints with encoded payloads
• PHP error logs indicating code execution attempts or eval-related errors

Detection Strategies

• Monitor web application firewall (WAF) logs for code injection patterns targeting WordPress login/signup endpoints
• Implement file integrity monitoring on WordPress plugin directories to detect unauthorized modifications
• Review WordPress user accounts for unexpected administrative users created without proper authorization
• Deploy endpoint detection solutions capable of identifying anomalous PHP process behavior

Monitoring Recommendations

• Enable verbose logging for the WordPress installation and review logs for suspicious activity
• Configure intrusion detection systems to alert on common PHP code injection patterns
• Monitor network traffic for outbound connections from the web server that may indicate successful compromise
• Implement real-time alerting for changes to critical WordPress files and database tables

How to Mitigate CVE-2025-49029

Immediate Actions Required

• Deactivate and remove the Custom Login And Signup Widget plugin immediately if version 1.0 or earlier is installed
• Audit WordPress installations for signs of compromise including unauthorized users or modified files
• Review server access logs for evidence of exploitation attempts
• If compromise is suspected, perform a complete security assessment and consider restoring from a known-good backup

Patch Information

At the time of publication, no patch has been confirmed for this vulnerability. Users are advised to remove the affected plugin until a security update is released by the developer. Monitor the Patchstack Vulnerability Report for updates on patch availability.

Workarounds

• Remove or deactivate the Custom Login And Signup Widget plugin until a patched version is available
• Implement a Web Application Firewall (WAF) with rules to block code injection attempts targeting WordPress plugins
• Use WordPress security plugins that provide virtual patching capabilities for known vulnerabilities
• Consider alternative login/signup plugins that have been recently audited for security issues

# Deactivate the vulnerable plugin via WP-CLI
wp plugin deactivate custom-login-and-signup-widget

# Remove the vulnerable plugin entirely
wp plugin delete custom-login-and-signup-widget

# List all admin users to check for unauthorized accounts
wp user list --role=administrator --fields=ID,user_login,user_email,user_registered