Security vulnerabilities

Attached to Project: Security vulnerabilities
Opened by Shivangi - 05.01.2026
Last edited by cbay - 05.01.2026

Description

The application allows users to upload files without properly validating the file content and type. An attacker can upload a malicious file (such as an HTML, SVG, or disguised image file) containing embedded JavaScript code. When the uploaded file is later accessed or rendered by other users, the malicious script executes in their browser context.

Because the payload is stored on the server and executed whenever the file is viewed, this issue qualifies as Stored (Persistent) XSS.

Impact

A successful Stored XSS attack may allow an attacker to:

Execute arbitrary JavaScript in victims’ browsers

Steal session cookies or authentication tokens

Perform actions on behalf of authenticated users

Deface application content

Deliver phishing payloads

Escalate to account takeover depending on session handling

This vulnerability affects all users who view or access the uploaded file, increasing its severity compared to reflected XSS.

Steps to Reproduce

Navigate to a file upload functionality.
Create a malicious file, for example:

<script>alert(document.domain)</script>

Save it as:

xss.pdf

Upload the malicious file through the application.

Access the uploaded file directly or via the application interface.

Observe that the JavaScript payload executes in the browser.