Overview
A stored Cross-Site Scripting (XSS) vulnerability has been discovered in the BrightTALK WordPress Shortcode plugin, identified as CVE-2025-11770. This vulnerability affects versions up to and including 2.4.0 of the plugin. It allows authenticated attackers with contributor-level access or higher to inject malicious JavaScript code into WordPress pages. This injected code will then execute whenever a user visits the compromised page, potentially leading to account compromise, data theft, or other malicious activities.
Technical Details
The vulnerability lies within the brighttalk-time shortcode, specifically in the format attribute. The plugin fails to properly sanitize user-supplied input for the format attribute and doesn’t adequately escape the output. This allows an attacker to inject arbitrary HTML and JavaScript code into the page content. The vulnerable code section is located in the brighttalk-wp-shortcode.php file.
Example of the vulnerable shortcode:
[brighttalk-time format="<img src=x onerror=alert('XSS')>"]An attacker can inject the above malicious code through a post or page, and when the page is rendered, the JavaScript will execute.
CVSS Analysis
The National Vulnerability Database (NVD) has assigned a CVSS score of 6.4 to CVE-2025-11770, indicating a MEDIUM severity.
The CVSS vector string provides a detailed breakdown:
- Attack Vector (AV): Network (N)
- Attack Complexity (AC): Low (L)
- Privileges Required (PR): Low (L)
- User Interaction (UI): Required (R)
- Scope (S): Changed (C)
- Confidentiality Impact (C): Low (L)
- Integrity Impact (I): Low (L)
- Availability Impact (A): None (N)
This means the vulnerability is remotely exploitable with low complexity, requires minimal privileges, and relies on user interaction. A successful exploit could lead to limited impacts on confidentiality and integrity.
Possible Impact
A successful exploitation of this vulnerability could have the following impacts:
- Account Compromise: Attackers could potentially steal user session cookies or credentials.
- Website Defacement: Malicious scripts could be injected to alter the appearance of the website.
- Redirection to Malicious Sites: Users could be redirected to phishing or malware distribution websites.
- Data Theft: Sensitive information displayed on the compromised page could be stolen.
Mitigation or Patch Steps
The recommended course of action is to:
- Update the Plugin: Check for a newer version of the BrightTALK WordPress Shortcode plugin that addresses this vulnerability. Update to the latest version as soon as it becomes available.
- Disable the Plugin (Temporary): If an update is not immediately available, consider temporarily disabling the plugin until a patched version is released.
- Web Application Firewall (WAF): Implement a Web Application Firewall (WAF) and configure it to block XSS attacks. This can provide an additional layer of protection.
- Input Sanitization and Output Encoding: Developers can improve the security of their code by sanitizing user inputs and encoding outputs properly.
References
- CVE ID: CVE-2025-11770
- Plugin Code: brighttalk-wp-shortcode.php#L130
- Wordfence Threat Intelligence: Wordfence Vulnerability Report
