Vulnerability · Published Jun 25, 2026 · Assigned by GitHub_M

CVE-2026-54030LibreChat: Missing Resource Parameter Validation in MCP OAuth Flow

High 8.0

In plain English

A high-severity security flaw in LibreChat from danny-avila. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 6% of all known vulnerabilities).

Severity (CVSS 3.1)8.0High

Exploit odds (30 days)0.2%top 93.9% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
danny-avila	LibreChat	< 0.8.5

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

References

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