CVE-2025-1485 – Real Cookie Banner < 5.1.6 – Stored XSS to JS Backdoor Creation – POC

The Real Cookie Banner plugin is a powerful consent management tool for WordPress, widely used to help website administrators comply with the GDPR and ePrivacy directives. With features like customizable cookie banners, content blockers, and consent documentation, the plugin plays a key role in user privacy and legal compliance. However, in version below 5.1.6, a Stored Cross-Site Scripting (XSS) vulnerability was discovered that can be exploited by authenticated users with access to the plugin’s customization features.

This article explores the vulnerability in detail, demonstrates how it can be exploited, and outlines practical recommendations for mitigating similar security risks in WordPress environments.

CVE	CVE-2025-1485
Plugin	Real Cookie Banner < 5.1.6
Critical	High
All Time	11 390 492
Active installations	100 000+
Publicly Published	May 13, 2025
Last Updated	May 13, 2025
Researcher	Artyom Krugov
OWASP TOP-10	A7: Cross-Site Scripting (XSS)
PoC	Yes
Exploit	No
Reference	https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-1485 https://wpscan.com/vulnerability/0158eb67-cd36-4406-bf70-6f2be849ec52/
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Logo of the plugin

Timeline

Discovery of the Vulnerability

The vulnerability, now tracked as CVE-2025-1485, was discovered during routine plugin analysis, revealing that the General Description field inside the Cookie Banner/Dialog Design tab fails to adequately sanitize and encode HTML input. This oversight enables a Contributor-level user or higher to inject malicious scripts that are executed when the banner or its preview is rendered.

Understanding of XSS attack’s

Stored XSS (Cross-Site Scripting) occurs when a web application stores user-supplied input that is later rendered as executable JavaScript/HTML in the browser of another user. Unlike Reflected XSS, which is immediate and usually tied to a specific URL, Stored XSS persists on the server and is triggered each time a page loads.

In WordPress, common targets for Stored XSS include:

• Post titles or content
• Custom fields
• Plugin settings
• User profiles
• Widgets

Real-world examples include:

• A Contributor injecting <script>alert(document.cookie)</script> into a post title, affecting admin users.
• A malicious payload embedded in a plugin’s configuration panel that executes every time an administrator opens it.

Exploiting the XSS Vulnerability

Exploitation Steps:

POC:

1) Login as a Aministrator or higher-privileged user.
2) Navigate to the Real Cookie Banner plugin section in the WordPress dashboard.
3) Open Banner Customization.
4) Go to the Text section under Cookie Banner/Dialog Design.
5) Insert the following payload in the General Description field:
"><script></script><img src=x onerror=alert(777)>
6) Click Save.

____

Once saved, the injected script is executed:

• Immediately in the preview.
• When the configuration page is loaded.
• Potentially by other users if they have access to this section.

Additionally, the Edit Banner URL can be shared to trick administrators into loading the page, leading to session hijacking, data exposure, or redirection to malicious sites.

Recommendations for Improved Security

To mitigate the risks posed by CVE-2025-1485, the following steps should be taken:

Immediate Actions:

• Update the Real Cookie Banner plugin to version 5.1.6 or later, which contains the fix for this vulnerability.

For Developers:

• Sanitize all user inputs using WordPress’s built-in functions:
  • sanitize_text_field() – for plain text.
  • wp_kses_post() – for safe HTML.
  • esc_html() / esc_attr() – when rendering outputs.
• Ensure output encoding is properly applied before rendering user-configurable fields, especially those that support custom text or HTML.
• Avoid rendering HTML directly from user inputs unless a strict allowlist of safe tags and attributes is enforced.

For Administrators:

• Restrict Contributor permissions: Use role management plugins to limit access to plugin settings and banner customization tabs.
• Implement a Content Security Policy (CSP) to reduce the impact of XSS by disallowing execution of inline or third-party scripts.
• Perform regular reviews of user roles and capabilities, especially in environments with multiple authors or contributors.
• Monitor plugin changelogs and apply updates promptly to maintain security compliance.

By addressing these issues and implementing strict input validation and secure output encoding, both plugin developers and WordPress administrators can significantly reduce the risk of persistent XSS attacks like CVE-2025-1485 in the future.

By taking proactive measures to address Stored XSS vulnerabilities like CVE-2025-2162, WordPress website owners can enhance their security posture and safeguard against potential exploitation. Stay vigilant, stay secure.

#WordPressSecurity #StoredXSS #WebsiteSafety #StayProtected #HighVulnerability

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Artyom k.