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 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.

CVSS v3 6.8 MEDIUM

6.8^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.3 / Impact : 4.0

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction REQUIRED

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Scope CHANGED

References

Link	Resource
https://github.com/danny-avila/LibreChat/security/advisories/GHSA-pmw7-gqwj-f954	Exploit Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:librechat:librechat::::::::
	cpe:2.3:a:librechat:librechat:0.8.3:rc1::::::

History

No history.

Information

Published : 2026-03-27 20:16

Updated : 2026-06-17 10:34

NVD link : CVE-2026-31951

Mitre link : CVE-2026-31951

CVE.ORG link : CVE-2026-31951

JSON object : View

Products Affected

librechat

librechat

CWE

CWE-200

Exposure of Sensitive Information to an Unauthorized Actor

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