Checkmarx AI Remediation - Stored_XSS

[checkmarx-gh-ast-us-povs]

Checkmarx One – Remediation

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Stored_XSS · Critical

Triage context: Reachable · Exploitable

Fix Stored XSS vulnerability in admin dashboard

What is the issue?
A Stored Cross-Site Scripting (XSS) vulnerability exists in the admin dashboard where user-controlled data from the database (project names, descriptions, and other fields) is rendered directly in HTML templates without sanitization. This allows attackers to inject malicious JavaScript code into the database, which then executes in the browsers of all users viewing the admin dashboard. The vulnerability enables session hijacking, credential theft, and unauthorized access to sensitive application data.

Why should it be fixed?
This is a critical vulnerability that allows attackers to execute arbitrary JavaScript in admin browsers, enabling session cookie theft, credential harvesting, and account takeover. Exploitation could lead to unauthorized access to all user and project data, regulatory violations (OWASP Top 10, CWE-79), and significant reputational damage. Immediate remediation is required to prevent potential data breaches and compliance violations.

How should it be fixed?
Add HTML output encoding to sanitize database content before rendering in templates. In backend/app.py, import markupsafe.escape and create a _sanitize_object_for_template() helper function that converts database objects to dictionaries with all string attributes escaped. Apply this sanitization function to the projects data at line 169 before passing to render_template(). In backend/test_xss_remediation.py, create a comprehensive test suite with 17 test cases validating that XSS payloads (script tags, event handlers, SVG-based attacks, JavaScript URLs) are properly escaped and cannot execute. Fix pre-existing syntax errors in app.py by correcting escaped docstrings.

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[checkmarx-gh-ast-us-povs]

Checkmarx One – Scan Summary & Details – c32a9970-a035-4710-ad88-4df1401ad663

Great job! No new security vulnerabilities introduced in this pull request

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Examples:
@Checkmarx how are you able to help me?
@Checkmarx rescan this PR