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The CVE-2025-65676 vulnerability operates through a stored cross-site scripting (XSS) mechanism within the Classroomio Learning Management System version 0.1.13. Authenticated attackers, such as instructors or users with upload privileges, can exploit this flaw by submitting a specially crafted SVG (Scalable Vector Graphics) file as a course cover image. SVG files can contain embedded JavaScript code within script tags or event handlers. The LMS application fails to properly validate and sanitize the SVG content during upload or when rendering the image on web pages. When the malicious SVG cover image is stored on the server and subsequently displayed to victims—such as students or administrators visiting the course page—the embedded JavaScript payload is executed in the victim’s browser context. This allows the attacker to perform arbitrary actions, including stealing session cookies, redirecting users, or performing actions on behalf of the victim, effectively compromising their account and data. The attack persists because the malicious image is permanently stored on the server, impacting all users who view the affected page.
Platform: Classroomio LMS
Version: 0.1.13
Vulnerability: Stored XSS
Severity: Critical
Date: 11/26/2025
Prediction: Patch by 01/2026
What Undercode Say:
Analytics:
echo '<svg xmlns="http://www.w3.org/2000/svg" onload="alert(document.cookie)"></svg>' > exploit.svg curl -X POST -F "[email protected]" -H "Authorization: Bearer <token>" https://target.com/upload
<!-- Sample malicious SVG payload -->
<svg>
<script>alert('XSS')</script>
</svg>
how Exploit:
Authenticated user uploads crafted SVG cover image. Server stores image without sanitization. Victim views page containing image. Embedded JavaScript executes in victim’s browser.
Protection from this CVE:
Sanitize SVG uploads. Implement Content Security Policy. Validate and encode user input.
Impact:
Session hijacking. Data theft. Unauthorized actions.
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Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
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