CVE-2025-15491: Post Slides WordPress LFI Vulnerability

CVE-2025-15491 Overview

CVE-2025-15491 is a Local File Inclusion (LFI) vulnerability affecting the Post Slides WordPress plugin through version 1.0.1. The plugin fails to properly validate shortcode attributes before using them to generate paths that are passed to PHP include functions. This allows authenticated users with contributor-level access or higher to perform LFI attacks, potentially exposing sensitive server files or enabling further exploitation.

Critical Impact

Authenticated attackers can leverage improper path validation in shortcode handling to include arbitrary local files, potentially exposing sensitive configuration data such as wp-config.php or system files like /etc/passwd.

Affected Products

• Post Slides WordPress plugin version 1.0.1 and earlier
• WordPress installations using the Post Slides plugin with contributor or higher user roles

Discovery Timeline

• 2026-02-07 - CVE-2025-15491 published to NVD
• 2026-02-09 - Last updated in NVD database

Technical Details for CVE-2025-15491

Vulnerability Analysis

This vulnerability is classified under CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), commonly known as Path Traversal. The Post Slides plugin implements shortcode functionality that accepts user-controlled attributes to dynamically generate file paths. These paths are subsequently passed to PHP's include() or similar functions without adequate validation or sanitization.

The flaw enables authenticated users to manipulate shortcode attributes by injecting path traversal sequences (such as ../) to escape the intended directory scope. This allows attackers to include files outside the plugin's designated directories, potentially accessing sensitive WordPress configuration files, system files, or other application data stored on the server.

Root Cause

The root cause stems from insufficient input validation on shortcode attributes that are used to construct file paths. The plugin accepts user-supplied values and directly concatenates them into file paths without implementing proper sanitization measures such as:

• Filtering or rejecting path traversal characters (../, ..\\)
• Validating that the resolved path remains within allowed directories
• Using WordPress's built-in sanitization functions for file operations

Attack Vector

The attack is network-based and requires authentication with at least contributor-level privileges on the WordPress site. An attacker with such access can craft malicious shortcode content containing path traversal sequences in the affected attributes.

When the shortcode is processed—either during content preview or when a page containing the shortcode is rendered—the manipulated path is passed to the include function, causing the server to read and potentially expose the contents of arbitrary local files.

The vulnerability allows attackers to traverse directory structures and include files such as WordPress configuration files containing database credentials, or system files that could aid in further attacks against the server infrastructure.

Detection Methods for CVE-2025-15491

Indicators of Compromise

• Unusual shortcode patterns in WordPress posts or pages containing ../ sequences
• Unexpected file access attempts in web server logs targeting sensitive files like wp-config.php or /etc/passwd
• Modified or suspicious content created by contributor-level users
• Error logs showing failed include attempts for files outside normal plugin directories

Detection Strategies

• Review WordPress content database for shortcodes with suspicious path traversal patterns in attributes
• Monitor web application firewall (WAF) logs for LFI attack signatures targeting the Post Slides plugin
• Audit user activity logs for contributor accounts creating or editing posts with unusual shortcode configurations
• Implement file integrity monitoring on critical WordPress files to detect unauthorized access

Monitoring Recommendations

• Enable and review PHP error logging for include-related warnings or errors
• Configure intrusion detection systems to alert on path traversal patterns in HTTP requests
• Implement real-time monitoring of access to sensitive configuration files
• Regularly audit WordPress user accounts and their associated content modifications

How to Mitigate CVE-2025-15491

Immediate Actions Required

• Deactivate and remove the Post Slides plugin immediately if not critical to site functionality
• Restrict contributor and author-level user accounts until the plugin is patched or removed
• Review all existing posts and pages for suspicious shortcode usage and remove any malicious content
• Implement a Web Application Firewall (WAF) with LFI protection rules

Patch Information

As of the last update, no official patch has been released for this vulnerability. Site administrators should monitor the WPScan Vulnerability Database Entry for updates on patch availability. Until a fix is released, removal of the plugin is the recommended course of action.

Workarounds

• Remove or deactivate the Post Slides plugin until a security patch is available
• Implement server-level restrictions using PHP's open_basedir directive to limit file inclusion scope
• Configure WAF rules to block requests containing path traversal sequences targeting WordPress shortcodes
• Limit contributor and author role capabilities using a WordPress security plugin to prevent shortcode creation or editing

Administrators can implement PHP configuration hardening by adding the following to their server configuration:

# Apache .htaccess or server configuration
# Restrict PHP open_basedir to limit file inclusion scope
php_value open_basedir "/var/www/html/wordpress:/tmp"

# Block common path traversal patterns
RewriteEngine On
RewriteCond %{QUERY_STRING} (\.\./|\.\.) [NC]
RewriteRule .* - [F,L]