CVE-2026-54030

LibreChat: Missing Resource Parameter Validation in MCP OAuth Flow

CVSS 8 HIGHEPSS 0.1%CWE-346

Vexday Risk Score

21Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 8EPSS 0.1%KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

25 Jun 2026Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

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.

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N

Affected products

danny-avila · LibreChat

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References

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