Description
LibreChat is a ChatGPT clone with additional features. In versions 0.8.2-rc1 through 0.8.3-rc1, user-created MCP (Model Context Protocol) servers can include arbitrary HTTP headers that undergo credential placeholder substitution. An attacker can create a malicious MCP server with headers containing `{{LIBRECHAT_OPENID_ACCESS_TOKEN}}` (and others), causing victims who call tools on that server to have their OAuth tokens exfiltrated. Version 0.8.3-rc2 fixes the issue.
Affected products
librechat: librechat
References1
- github.com/danny-avila/LibreChat/security/advisories/GHSA-pmw7-… ExploitVendor Advisory
Metrics
- CVSS 3.1
-
5.7
MEDIUM
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N - EPSS — exploit probability
- 0% percentile: 17 · as of 12 November 2026
- CWE
- CWE-200
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