CVE-2025-50733: XSS (CVSS 6.1)

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.

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CVSS v3.1 Score

6.1

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

References

Other References

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

Frequently Asked Questions

What is CVE-2025-50733? +

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. It has a CVSS v3.1 base score of 6.1 (MEDIUM).

How severe is CVE-2025-50733? +

CVE-2025-50733 has a CVSS v3.1 score of 6.1 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

How do I check if I'm vulnerable to CVE-2025-50733? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2025-50733