CVE-2026-31951 | BDVDB-2026-323404 Detail

Description#

LibreChat is a ChatGPT clone with additional features. In versions 0.8.2-rc1 through 0.8.3-rc1, user-created MCP (Model Context Protocol) servers can include arbitrary HTTP headers that undergo credential placeholder substitution. An attacker can create a malicious MCP server with headers containing `{{LIBRECHAT_OPENID_ACCESS_TOKEN}}` (and others), causing victims who call tools on that server to have their OAuth tokens exfiltrated. Version 0.8.3-rc2 fixes the issue.

Impact#

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Exploit#

History#

1. Version 12026-03-27Record published in the CVE List.
2. Version 22026-03-31Most recent update recorded in the CVE List.