CVE-2026-54030

HIGH

LibreChat: Missing Resource Parameter Validation in MCP OAuth Flow

Title source: cna
STIX 2.1

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.

References (1)

Core 1
Core References

Scores

CVSS v3 8.0
EPSS 0.0013
EPSS Percentile 3.0%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N

CISA SSVC

Vulnrichment
Exploitation poc
Automatable no
Technical Impact total

Details

CWE
CWE-346
Status published
Products (3)
danny-avila/LibreChat < 0.8.5
librechat/librechat 0.8.5 rc1
librechat/librechat < 0.8.4
Published Jun 25, 2026
Tracked Since Jun 25, 2026