CVE-2026-31951: LibreChat is a ChatGPT clone with additional features. In versions 0.8.2-rc1 through 0.8.3-rc1, user-created MCP (Model

LibreChat versions 0.8.2-rc1 through 0.8.3-rc1 have a vulnerability where user-created MCP (Model Context Protocol, a system for connecting AI models to external tools) servers can steal OAuth tokens (security credentials used for authentication). An attacker can create a malicious MCP server with special headers that trick LibreChat into substituting sensitive tokens, which are then leaked when victims use tools on that server.