Description

NextChat contains a cross-site scripting (XSS) vulnerability in the HTMLPreview component of artifacts.tsx that allows attackers to execute arbitrary JavaScript code when HTML content is rendered in the AI chat interface. The vulnerability occurs because user-influenced HTML from AI responses is rendered in an iframe with 'allow-scripts' sandbox permission without proper sanitization. This can be exploited through specifically crafted prompts that cause the AI to generate malicious HTML/JavaScript code. When a user views the HTML preview, the injected JavaScript executes in the user's browser context, potentially allowing attackers to exfiltrate sensitive information (including API keys stored in localStorage), perform actions on behalf of the user, and steal session data.

Weaknesses 1

References 2

• github.com https://github.com/fai1424/Vulnerability-Research/blob/main/CVE-2025-50733/README.md
• hackmd.io https://hackmd.io/@fai1424/BkgqMnNxgl

Remediation