CVE-2026-54030

LibreChat: Missing Resource Parameter Validation in MCP OAuth Flow

State: Published
Severity: 8.0 High
Published: Jun 25, 2026
Updated: Jun 26, 2026
Reserved: Jun 11, 2026

Description

LibreChat is an enhanced ChatGPT clone that supports multiple AI providers. Prior to 0.8.5, LibreChat's MCP OAuth implementation does not validate that the resource parameter from OAuth Protected Resource metadata (RFC 9728) matches the configured MCP server URL, allowing a malicious MCP server to steal access tokens intended for a legitimate server. This vulnerability is fixed in 0.8.5.

Scores

CVSS	Score	Vector	Source
3.1	8.0 High	CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N	GitHub_M

Weaknesses

CWE-346 Origin Validation Error

Affected Products

Product	Versions
LibreChatdanny-avila	< 0.8.5Affected

References

https://github.com/danny-avila/LibreChat/security/advisories/GHSA-gvpj-vm2f-2m23

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