CVE-2026-31951

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.

PUBLISHED Reserved 2026-03-10 | Published 2026-03-27 | Updated 2026-03-31 | Assigner GitHub_M

Problem types

CWE-200: Exposure of Sensitive Information to an Unauthorized Actor

Product status

References

github.com/...reChat/security/advisories/GHSA-pmw7-gqwj-f954

cve.org (CVE-2026-31951)

nvd.nist.gov (CVE-2026-31951)

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