CVE-2025-1509: Show Me The Cookies RCE Vulnerability

CVE-2025-1509 Overview

The Show Me The Cookies plugin for WordPress contains an arbitrary shortcode execution vulnerability affecting all versions up to and including 1.0. The vulnerability stems from improper input validation when processing user-controlled values before passing them to the WordPress do_shortcode() function. This security flaw allows unauthenticated attackers to execute arbitrary shortcodes on vulnerable WordPress installations, potentially leading to complete site compromise.

Critical Impact

Unauthenticated attackers can execute arbitrary WordPress shortcodes, enabling potential remote code execution, data exfiltration, and full site takeover depending on other plugins installed.

Affected Products

• wpguru Show Me The Cookies version 1.0 and earlier
• WordPress sites running the Show Me The Cookies plugin

Discovery Timeline

• 2025-02-22 - CVE-2025-1509 published to NVD
• 2025-03-06 - Last updated in NVD database

Technical Details for CVE-2025-1509

Vulnerability Analysis

This vulnerability is classified as Code Injection (CWE-94) and allows unauthenticated attackers to execute arbitrary WordPress shortcodes. The flaw exists because the plugin fails to properly validate user-supplied input before processing it through the WordPress do_shortcode() function.

WordPress shortcodes are powerful macros that can execute complex functionality, including those provided by other installed plugins. When an attacker can inject arbitrary shortcodes, they may be able to leverage other plugin functionality to escalate the attack to remote code execution, access sensitive database information, create administrative accounts, or modify site content.

The attack is particularly dangerous because it requires no authentication, meaning any remote attacker with network access to the vulnerable WordPress installation can exploit this flaw. The attack complexity is low, requiring no special conditions or user interaction to succeed.

Root Cause

The root cause of this vulnerability lies in the absence of proper input validation and sanitization. The plugin implements an action that accepts user input and directly passes it to the do_shortcode() function without verifying that the input contains only expected or safe values. This violates the principle of defense in depth and allows attackers to inject malicious shortcode directives.

Attack Vector

The vulnerability is exploitable over the network without requiring authentication. An attacker can craft malicious HTTP requests containing shortcode payloads that the plugin will execute. The attack surface is significant because:

1. No authentication is required to trigger the vulnerable code path
2. No user interaction is needed for exploitation
3. The attack can be executed remotely over HTTP/HTTPS
4. Successful exploitation can lead to confidentiality, integrity, and availability impacts

The vulnerability exploitation depends on which other plugins are installed on the WordPress site. Sites with plugins that register dangerous shortcodes (such as those allowing file operations, database queries, or code execution) face the highest risk.

For detailed technical analysis, see the Wordfence Vulnerability Analysis.

Detection Methods for CVE-2025-1509

Indicators of Compromise

• Unexpected or suspicious shortcode execution entries in WordPress debug logs
• Unusual POST requests to WordPress AJAX handlers or plugin endpoints containing shortcode syntax (brackets [ and ])
• New administrative user accounts created without legitimate authorization
• Unexplained modifications to site content, themes, or plugins
• Evidence of other installed plugin shortcodes being invoked unexpectedly

Detection Strategies

• Monitor web server access logs for suspicious POST requests containing shortcode patterns targeting plugin endpoints
• Implement Web Application Firewall (WAF) rules to detect and block requests containing shortcode injection attempts
• Review WordPress audit logs for unauthorized shortcode executions or administrative actions
• Deploy file integrity monitoring to detect unauthorized modifications to WordPress core files, themes, and plugins

Monitoring Recommendations

• Enable WordPress debug logging and monitor for shortcode-related errors or warnings
• Configure SIEM alerts for patterns matching shortcode injection attempts (e.g., requests containing [ followed by potential shortcode names)
• Regularly audit installed WordPress plugins to identify which shortcodes are registered and their potential impact if abused
• Monitor for anomalous outbound network connections from the WordPress server that could indicate post-exploitation activity

How to Mitigate CVE-2025-1509

Immediate Actions Required

• Immediately deactivate and remove the Show Me The Cookies plugin version 1.0 or earlier from all WordPress installations
• Audit WordPress installations for signs of compromise, including unauthorized users, modified files, or suspicious database entries
• Review other installed plugins to assess shortcode-related attack surface and remove any unnecessary plugins
• Implement a Web Application Firewall (WAF) with rules to block shortcode injection attempts as a temporary protective measure

Patch Information

At the time of publication, no patched version of the Show Me The Cookies plugin has been identified in the available CVE data. Site administrators should check the WordPress Plugin Directory for any security updates or consider permanently removing the plugin if no update is available.

Until a patch is released, the plugin should be considered unsafe for production use. Contact the vendor (wpguru) for information about a security fix or alternative solutions.

Workarounds

• Remove the Show Me The Cookies plugin entirely from WordPress installations until a security patch is available
• If the plugin functionality is critical, restrict access to the WordPress admin and frontend using IP allowlisting at the web server or firewall level
• Implement WAF rules to filter requests containing shortcode patterns to vulnerable endpoints
• Conduct a security audit of all installed WordPress plugins and remove those with unnecessary or dangerous shortcode functionality

# WordPress CLI commands to identify and remove the vulnerable plugin
# List installed plugins and their versions
wp plugin list --status=active

# Deactivate the vulnerable plugin
wp plugin deactivate show-me-the-cookies

# Remove the vulnerable plugin entirely
wp plugin delete show-me-the-cookies

# Search for any suspicious users that may have been created
wp user list --role=administrator