CVE-2025-66452: LibreChat cross-site scripting through unhandled JSON parsing errors

Summary

CVE-2025-66452 affects LibreChat versions 0.8.0 and below. The application has no handler for JSON parsing errors, so a SyntaxError from express.json() includes user input in its error message, which is reflected in responses. Attacker-supplied HTML or JavaScript can therefore appear in error responses, creating an XSS risk when Content-Type is not strictly enforced.

Mitigation

The source does not state a fix yet. Check the original advisory for updates.

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