LibreChat is a ChatGPT clone with additional features. From 0.8.2 to 0.8.2-rc3, The MCP (Model Context Protocol) OAuth callback endpoint accepts the redirect from the identity provider and stores OAuth tokens for the user who initiated the flow, without verifying that the browser hitting the redirect URL is logged in or that the logged-in user matches the initiator. An attacker can send the authorization URL to a victim; when the victim completes the flow, the victim’s OAuth tokens are stored on the attacker’s LibreChat account, enabling account takeover of the victim’s MCP-linked services (e.g. Atlassian, Outlook). This vulnerability is fixed in 0.8.3-rc1.

LibreChat is a ChatGPT clone with additional features. Prior to 0.8.3-rc1, a Denial of Service (DoS) vulnerability exists in the DELETE /api/convos endpoint that allows an authenticated attacker to crash the Node.js server process by sending malformed requests. The DELETE /api/convos route handler attempts to destructure req.body.arg without validating that it exists. The server crashes due to an unhandled TypeError that bypasses Express error handling middleware and triggers process.exit(1). This vulnerability is fixed in 0.8.3-rc1.