Overview
CVE-2025-13907 is a Stored Cross-Site Scripting (XSS) vulnerability found in the CSS3 Buttons plugin for WordPress. This vulnerability affects all versions up to and including 0.1. It allows authenticated attackers with contributor-level access or higher to inject arbitrary web scripts into WordPress pages. These scripts will execute whenever a user accesses the compromised page, potentially leading to account compromise, data theft, or other malicious activities.
Technical Details
The vulnerability resides within the plugin’s handling of the button shortcode. Due to insufficient input sanitization and output escaping on user-supplied attributes within the shortcode, malicious JavaScript code can be injected. For example, an attacker could insert a crafted shortcode like this:
[button link="#" title="<img src=x onerror=alert('XSS')>" color="blue"]Click Me[/button]When this shortcode is rendered on a page, the JavaScript code within the title attribute will execute. The core issue is the lack of proper filtering of potentially malicious characters before they are rendered in the HTML output.
CVSS Analysis
- CVE ID: CVE-2025-13907
- Severity: MEDIUM
- CVSS Score: 6.4
This CVSS score reflects the moderate severity of the vulnerability. While it requires authentication, the low privileges needed (contributor) and the potential impact of executing arbitrary code in a user’s browser justify this rating.
Possible Impact
A successful exploit of this vulnerability could have several serious consequences:
- Account Compromise: An attacker could steal user cookies or other sensitive information, allowing them to impersonate users and gain access to their accounts.
- Data Theft: Malicious scripts could be used to exfiltrate sensitive data from the WordPress site or the user’s browser.
- Redirection to Malicious Sites: Users could be redirected to phishing sites or other malicious websites.
- Website Defacement: An attacker could modify the content of the website, defacing it or injecting malicious code into other pages.
Mitigation or Patch Steps
Unfortunately, since the CSS3 Buttons plugin has not been updated and contains vulnerable code within its codebase, the most effective solution is to remove the plugin entirely from your WordPress installation. If the plugin offers critical functionality, you should find and install a similar plugin from a reputable developer that actively provides security updates.
Here are general hardening steps to prevent future XSS vulnerabilities:
- Use a Web Application Firewall (WAF): A WAF can help to detect and block malicious requests, including those that attempt to exploit XSS vulnerabilities.
- Keep WordPress and Plugins Updated: Regularly update WordPress core, themes, and plugins to patch known security vulnerabilities.
- Implement Strict Input Validation and Output Encoding: Ensure that all user input is properly validated and sanitized before being stored in the database or displayed on the website. Use appropriate output encoding techniques to prevent malicious code from being executed in the browser.
- Limit User Privileges: Grant users only the minimum privileges necessary to perform their tasks. Avoid granting contributor access unless absolutely necessary.