CVE-2026-54030

PoC —

CVSS 3.1

9.3 critical

EPSS

<1%p6

Published

Jun 25, 2026 (Jun 25, 2026)

Modified

Jun 29, 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.

Vendors: librechat
Products: librechat
Weakness: CWE-346
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

NVD CVE.org GitHub PoCs EPSS (0.2%)

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