Submit #994199: Privoce vocechat <=0.9.121 Improper Neutralization of Alternate XSS Syntax

The welcome query parameter on the widget.html page is not sanitized or encoded before being written directly into a dangerous DOM sink (e.g., innerHTML) by client-side JavaScript, resulting in a DOM-based Cross-Site Scripting (XSS) vulnerability. An attacker can craft a malicious link that, when clicked by a victim, executes arbitrary JavaScript in the victim's browser session. This can be used to exfiltrate sensitive client-side data such as localStorage, sessionStorage, or accessible cookies, as well as to perform session hijacking, phishing, or malicious redirects.

Proof of Concept: http://localhost:3001/widget.html?welcome=<img src=x onerror="alert(JSON.stringify(localStorage))">

Trigger condition: Victim visits a link containing the malicious welcome parameter.

Root cause: User-controllable input from the URL is not HTML-escaped or sanitized before being inserted into a DOM-rendering sink on the client side.

• Source: ⚠️ https://github.com/H1ck1y/Vulnerabilities/blob/main/Vocechat_DomXss.md
• User: dyihan (UID 101533)
• Submission: 09/22/2026 15:21 (1 month ago)
• Moderation: 10/24/2026 16:00 (1 month later)
• Status: Accepted
• VulDB entry: 426123 [Privoce Vocechat up to 0.9.121 Query Parameter widget.html welcome cross site scripting]
• Points: 20