CVE-2026-27540: WooCommerce Wholesale Lead Capture RCE

CVE-2026-27540 Overview

CVE-2026-27540 is an Unrestricted Upload of File with Dangerous Type vulnerability (CWE-434) affecting the WooCommerce Wholesale Lead Capture plugin developed by Rymera Web Co Pty Ltd. This critical vulnerability allows attackers to upload malicious files to vulnerable WordPress installations, potentially leading to complete site compromise and remote code execution.

The vulnerability exists because the plugin fails to properly validate file types during the upload process, enabling attackers to bypass security restrictions and upload executable files such as PHP web shells. Once uploaded, these malicious files can be executed on the server, granting attackers full control over the affected WordPress site.

Critical Impact

Unauthenticated attackers can upload malicious files to WordPress sites running vulnerable versions, potentially achieving remote code execution and complete site takeover.

Affected Products

• WooCommerce Wholesale Lead Capture plugin versions up to and including 2.0.3.1
• WordPress sites running vulnerable versions of the plugin
• E-commerce sites utilizing WooCommerce with the Wholesale Lead Capture extension

Discovery Timeline

• 2026-03-19 - CVE-2026-27540 published to NVD
• 2026-03-19 - Last updated in NVD database

Technical Details for CVE-2026-27540

Vulnerability Analysis

This vulnerability represents a classic unrestricted file upload flaw that bypasses intended security controls. The WooCommerce Wholesale Lead Capture plugin fails to implement proper server-side validation of uploaded file types, allowing attackers to upload files with dangerous extensions such as .php, .phtml, or other executable formats.

The attack can be executed remotely over the network without requiring authentication. While the attack complexity is rated as high due to specific conditions that must be met, successful exploitation results in severe consequences including complete compromise of confidentiality, integrity, and availability of the target system. The scope is changed, meaning the vulnerability can affect resources beyond the vulnerable component itself, potentially impacting the entire web server and other hosted applications.

Root Cause

The root cause of CVE-2026-27540 lies in insufficient input validation within the file upload functionality of the WooCommerce Wholesale Lead Capture plugin. The plugin does not adequately verify that uploaded files conform to an allowlist of safe file types before storing them in accessible directories on the web server.

Key contributing factors include:

• Missing or bypassable file extension checks
• Lack of MIME type validation
• Failure to sanitize uploaded file content
• Uploaded files being stored in publicly accessible directories with executable permissions

Attack Vector

The attack leverages the network-accessible file upload functionality within the plugin. An attacker can craft a malicious HTTP request containing a dangerous file disguised or directly uploaded with an executable extension.

The exploitation flow typically involves:

1. Reconnaissance: Attacker identifies a WordPress site running a vulnerable version of the WooCommerce Wholesale Lead Capture plugin
2. Payload Preparation: Attacker prepares a malicious file, typically a PHP web shell
3. Upload Request: Attacker submits the malicious file through the plugin's upload endpoint, bypassing any client-side restrictions
4. Execution: Once uploaded, the attacker accesses the uploaded file directly via its URL, triggering code execution on the server
5. Compromise: With code execution achieved, the attacker can perform arbitrary actions including database access, lateral movement, and persistent access establishment

For detailed technical information, see the Patchstack Vulnerability Advisory.

Detection Methods for CVE-2026-27540

Indicators of Compromise

• Presence of unexpected PHP files or web shells in WordPress upload directories, particularly within plugin-related folders
• Suspicious HTTP POST requests to plugin upload endpoints containing file attachments with executable extensions
• Newly created files with execution timestamps that don't correlate with legitimate administrative activity
• Outbound network connections from the web server to unknown command and control infrastructure

Detection Strategies

• Monitor web server access logs for POST requests to WooCommerce Wholesale Lead Capture plugin endpoints followed by GET requests to newly created files in upload directories
• Implement file integrity monitoring (FIM) on WordPress directories to detect unauthorized file creation or modification
• Deploy web application firewall (WAF) rules to block file uploads containing PHP code or suspicious file extensions
• Utilize SentinelOne's behavioral detection capabilities to identify post-exploitation activity such as web shell execution

Monitoring Recommendations

• Enable verbose logging for file upload operations within WordPress and review logs regularly for anomalies
• Configure real-time alerts for new executable file creation in web-accessible directories
• Monitor process execution chains for web server processes spawning unexpected child processes (e.g., apache or nginx spawning /bin/bash)

How to Mitigate CVE-2026-27540

Immediate Actions Required

• Update the WooCommerce Wholesale Lead Capture plugin to the latest patched version immediately
• Audit WordPress upload directories for suspicious or unexpected files that may indicate prior exploitation
• Review web server access logs for evidence of exploitation attempts
• Consider temporarily disabling the plugin if an immediate update is not possible

Patch Information

Organizations should update the WooCommerce Wholesale Lead Capture plugin to a version newer than 2.0.3.1. Check the official WordPress plugin repository or the vendor's website for the latest secure release.

For additional details and patch availability, refer to the Patchstack Vulnerability Advisory.

Workarounds

• Implement a Web Application Firewall (WAF) rule to block file uploads with dangerous extensions to the affected plugin's endpoints
• Restrict access to the plugin's upload functionality via .htaccess rules or web server configuration
• Disable the affected plugin entirely until a patch can be applied
• Ensure WordPress upload directories are not directly executable by configuring appropriate server directives

# Apache configuration to prevent PHP execution in upload directories
# Add to .htaccess in the wp-content/uploads directory
<FilesMatch "\.php$">
    SetHandler None
    ForceType text/plain
</FilesMatch>

# Alternatively, use server configuration
<Directory "/var/www/html/wp-content/uploads">
    php_admin_flag engine off
</Directory>