Overview
A stored Cross-Site Scripting (XSS) vulnerability has been identified in Classroomio LMS version 0.1.13. This vulnerability, tracked as CVE-2025-65676, allows authenticated attackers to inject arbitrary web scripts that execute in other users’ browsers. The vulnerability stems from insufficient sanitization of user-supplied input in SVG cover images.
Technical Details
The vulnerability lies in the way Classroomio LMS handles SVG files uploaded as cover images. An attacker can craft a malicious SVG file containing embedded JavaScript code. When a user views a page that displays this image (e.g., a course page, profile page), the embedded JavaScript will execute within their browser session. This is possible because the application fails to properly sanitize the SVG file before storing and serving it. The attacker must be authenticated to upload an image.
CVSS Analysis
Currently, the CVSS score for CVE-2025-65676 is listed as N/A. While the severity is also indicated as N/A, the potential impact of a stored XSS vulnerability should not be underestimated. Even without a formal CVSS score, it’s crucial to address this vulnerability immediately.
Possible Impact
The impact of this stored XSS vulnerability can be significant. A successful exploit could allow an attacker to:
- Steal user session cookies, leading to account hijacking.
- Deface the website, altering content or redirecting users to malicious sites.
- Spread malware to users visiting affected pages.
- Gain administrative privileges by compromising an administrator account.
- Collect sensitive information, such as student data or financial information, depending on what is stored in the LMS.
Mitigation and Patch Steps
To mitigate this vulnerability, consider the following steps:
- Upgrade Classroomio LMS: Check the Classroomio official website for updated versions of the LMS that address this vulnerability. Upgrade to the latest version as soon as possible.
- Input Validation and Sanitization: Implement robust input validation and sanitization on all user-supplied data, particularly for file uploads. Use a library specifically designed for sanitizing SVG files to remove potentially malicious code.
- Content Security Policy (CSP): Implement a strong Content Security Policy (CSP) to restrict the sources from which the browser can load resources. This can help prevent the execution of injected scripts.
- Regular Security Audits: Conduct regular security audits and penetration testing to identify and address potential vulnerabilities in your LMS.
