CVE-2026-1405: WordPress Slider Future Plugin RCE Flaw

CVE-2026-1405 Overview

The Slider Future plugin for WordPress contains a critical arbitrary file upload vulnerability due to missing file type validation in the slider_future_handle_image_upload function. This security flaw affects all versions up to and including 1.0.5, allowing unauthenticated attackers to upload arbitrary files to the affected site's server, potentially enabling remote code execution.

Critical Impact

Unauthenticated remote attackers can upload malicious files including PHP web shells, enabling complete server compromise and remote code execution without any authentication requirements.

Affected Products

• Slider Future WordPress Plugin version 1.0.5 and earlier
• WordPress installations with the Slider Future plugin installed
• Web servers hosting affected WordPress sites

Discovery Timeline

• February 19, 2026 - CVE-2026-1405 published to NVD
• February 19, 2026 - Last updated in NVD database

Technical Details for CVE-2026-1405

Vulnerability Analysis

This vulnerability is classified under CWE-434 (Unrestricted Upload of File with Dangerous Type). The slider_future_handle_image_upload function in the Slider Future plugin fails to implement proper file type validation when processing uploaded files. The function accepts file uploads intended for slider images but does not verify that the uploaded content is actually an image file. This oversight allows attackers to bypass intended security controls and upload executable files such as PHP scripts.

The network-accessible attack vector combined with the lack of authentication requirements makes this vulnerability particularly dangerous. An attacker can exploit this flaw remotely without any user interaction or prior privileges on the target system. The successful exploitation leads to complete compromise of confidentiality, integrity, and availability of the affected system.

Root Cause

The root cause lies in the absence of file type validation within the slider_future_handle_image_upload function located at line 177 of slider-future.php. The function processes incoming file uploads without verifying:

• File extension whitelist validation
• MIME type verification
• File content inspection (magic bytes)
• Server-side file type determination

This allows any file type to be uploaded and stored on the server, including executable PHP files that can be directly accessed and executed via web requests.

Attack Vector

The attack is conducted over the network against WordPress installations running the vulnerable plugin. An unauthenticated attacker crafts a malicious HTTP POST request to the image upload endpoint exposed by the Slider Future plugin. By submitting a PHP file disguised as an image upload, the attacker can place executable code on the server.

Once uploaded, the malicious file can typically be accessed directly via a predictable URL path within the WordPress uploads directory. Upon accessing this file, the PHP code executes with the web server's privileges, granting the attacker a web shell with full control over the compromised system. This can lead to data theft, website defacement, lateral movement within the network, and use of the compromised server for further attacks.

The vulnerability mechanism involves submitting a crafted multipart form request to the plugin's upload handler. The slider_future_handle_image_upload function processes the request without validating the file type, saving the uploaded content directly to the server's file system. Technical details are available in the WordPress Plugin File Reference and the Wordfence Vulnerability Report.

Detection Methods for CVE-2026-1405

Indicators of Compromise

• Unexpected PHP files or web shells appearing in WordPress upload directories (typically wp-content/uploads/slider-future/)
• HTTP POST requests to the Slider Future plugin's upload endpoints from external or suspicious IP addresses
• New or modified files with executable extensions (.php, .phtml, .phar) in plugin-related directories
• Unusual outbound network connections originating from the web server process

Detection Strategies

• Monitor web server access logs for POST requests targeting /wp-content/plugins/slider-future/ endpoints
• Implement file integrity monitoring (FIM) on the WordPress uploads directory to detect unauthorized file creations
• Deploy web application firewalls (WAF) with rules to block file uploads containing PHP code patterns
• Use endpoint detection and response (EDR) solutions to identify suspicious file write operations by web server processes

Monitoring Recommendations

• Enable verbose logging on the web server to capture full request details including uploaded file names
• Configure security information and event management (SIEM) alerts for file creation events in web-accessible directories
• Periodically scan the WordPress installation for unexpected PHP files using security scanning tools
• Monitor for anomalous process spawning from PHP or web server parent processes

How to Mitigate CVE-2026-1405

Immediate Actions Required

• Immediately deactivate and remove the Slider Future plugin from all WordPress installations
• Audit upload directories for any suspicious or unexpected files that may have been uploaded
• Implement strict file upload restrictions at the web server level using configuration directives
• Deploy a web application firewall (WAF) with rules specifically blocking PHP file uploads to plugin directories

Patch Information

At the time of publication, organizations should refer to the Wordfence Vulnerability Report for the latest patch status and recommended remediation steps. Users should monitor the WordPress plugin repository for updated versions of Slider Future that address this vulnerability.

Workarounds

• Remove or disable the Slider Future plugin until a patched version is available
• Implement server-side restrictions to prevent execution of PHP files in the uploads directory using .htaccess or web server configuration
• Use WordPress security plugins to add additional file upload validation layers
• Restrict access to the plugin's upload functionality via IP whitelisting if the plugin cannot be removed

# Apache .htaccess configuration to prevent PHP execution in uploads
# Place this file in wp-content/uploads/slider-future/

<FilesMatch "\.(?:php|phtml|phar|php5|php7)$">
    Require all denied
</FilesMatch>

# Alternative using php_flag
<IfModule mod_php.c>
    php_flag engine off
</IfModule>