CVE-2026-31951
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.
- CVSS 3.1
- 5.7
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N - EPSS
- 0.3% chance of exploitation in the next 30 days; higher than 16% of CVEs (scores of 2026-10-26)
- CWE
- CWE-200
- Published
- Modified
- Record from
- the NVD, synced
Affected
- librechat:librechat