CVE-2025-26927: EPC AI Hub File Upload RCE Vulnerability

CVE-2025-26927 Overview

CVE-2025-26927 is a critical unrestricted file upload vulnerability affecting the EPC AI Hub WordPress plugin. This vulnerability allows unauthenticated attackers to upload arbitrary files with dangerous types, including web shells, directly to the web server. Successful exploitation enables complete server compromise through remote code execution capabilities.

Critical Impact

Unauthenticated attackers can upload malicious web shells to WordPress servers running vulnerable versions of AI Hub, leading to complete site takeover and potential server compromise.

Affected Products

• EPC AI Hub WordPress Plugin versions through 1.3.3
• WordPress installations with vulnerable AI Hub plugin installed
• Web servers hosting WordPress sites with the affected plugin

Discovery Timeline

• 2025-04-15 - CVE-2025-26927 published to NVD
• 2025-04-16 - Last updated in NVD database

Technical Details for CVE-2025-26927

Vulnerability Analysis

This vulnerability falls under CWE-434 (Unrestricted Upload of File with Dangerous Type), a well-documented weakness where applications fail to properly validate or restrict file types during upload operations. The AI Hub plugin lacks adequate file type validation mechanisms, allowing attackers to bypass intended restrictions and upload executable files such as PHP web shells.

The attack can be executed remotely over the network without requiring any authentication or user interaction. The scope of this vulnerability extends beyond the vulnerable component itself, potentially affecting the entire hosting infrastructure. Successful exploitation results in complete compromise of confidentiality, integrity, and availability of the affected system.

Root Cause

The root cause of CVE-2025-26927 lies in the AI Hub plugin's failure to implement proper server-side file validation. The plugin does not adequately verify uploaded file contents, relying potentially on easily spoofable client-side checks or filename extensions alone. Without robust MIME type verification, content inspection, or allowlist-based file type restrictions, malicious actors can upload arbitrary PHP files that execute with web server privileges.

Attack Vector

The attack vector for this vulnerability is network-based with no authentication requirements. An attacker can exploit this vulnerability by:

1. Identifying a WordPress installation running a vulnerable version of AI Hub (through 1.3.3)
2. Locating the file upload endpoint exposed by the plugin
3. Crafting a malicious PHP web shell payload
4. Submitting the web shell through the unrestricted upload functionality
5. Accessing the uploaded shell directly via the web server to execute arbitrary commands

The vulnerability requires no special privileges or user interaction, making it highly exploitable in automated attack scenarios. Once a web shell is uploaded, attackers gain persistent remote access to execute commands, exfiltrate data, deploy ransomware, or pivot to other systems on the network.

Detection Methods for CVE-2025-26927

Indicators of Compromise

• Unexpected PHP files appearing in WordPress upload directories or plugin folders
• Web server logs showing access to unusual .php files in upload paths
• Outbound network connections from the web server to unknown IP addresses
• New or modified files with suspicious names (e.g., shell.php, cmd.php, backdoor.php)
• Unusual process execution originating from web server processes (www-data, apache, nginx)

Detection Strategies

• Monitor file system changes in WordPress directories, particularly wp-content/uploads/ and plugin directories
• Implement web application firewall (WAF) rules to detect common web shell patterns in uploads
• Review web server access logs for POST requests to AI Hub plugin endpoints followed by suspicious GET requests
• Deploy file integrity monitoring (FIM) to detect unauthorized file additions or modifications
• Utilize endpoint detection and response (EDR) solutions to identify post-exploitation behaviors

Monitoring Recommendations

• Enable detailed logging for all file upload operations on WordPress installations
• Configure alerts for new PHP file creation in web-accessible directories
• Monitor for command execution patterns typical of web shell activity (whoami, id, uname, cat /etc/passwd)
• Implement network traffic analysis to detect command and control communications
• Regularly scan web directories for known web shell signatures using security scanning tools

How to Mitigate CVE-2025-26927

Immediate Actions Required

• Update the AI Hub plugin to the latest patched version immediately if a fix is available
• If no patch is available, deactivate and remove the AI Hub plugin until a security update is released
• Audit WordPress installations to identify any existing web shells or unauthorized files
• Review web server access logs for evidence of prior exploitation attempts
• Implement network-level restrictions to limit access to WordPress admin and upload endpoints

Patch Information

Organizations should monitor the Patchstack vulnerability database for official patch announcements and updated plugin versions. Until a patch is released, the plugin should be considered unsafe for production use.

Workarounds

• Disable or remove the AI Hub plugin entirely until an official security patch is released
• Implement web application firewall rules to block file upload requests to AI Hub endpoints
• Restrict file upload directories with .htaccess rules to prevent PHP execution
• Configure web server to deny execution of PHP files in upload directories
• Use server-side MIME type validation as an additional layer of defense if maintaining the plugin is necessary

# Apache .htaccess configuration to prevent PHP execution in uploads
# Place this in your WordPress uploads directory

<FilesMatch "\.(?i:php|php3|php4|php5|phtml)$">
    Order Deny,Allow
    Deny from all
</FilesMatch>

# Alternative: Disable PHP processing entirely in directory
php_flag engine off