CVE-2026-71424 PUBLISHED

Onyx: Cross-user OAuth-token leak via /api/mcp/servers* for per-user MCP servers

Assigner: GitHub_M
Reserved: 06.08.2026 Published: 17.08.2026 Updated: 17.08.2026

Onyx is an open-source AI platform. Prior to 3.1.10, 3.2.14, and 4.0.0, Onyx's GET /api/mcp/servers and GET /api/mcp/servers/persona/{persona_id} endpoints expose another user's OAuth Authorization header because OnyxTokenStorage.set_tokens and OnyxTokenStorage.set_client_info in backend/onyx/server/features/mcp/api.py copy per-user tokens into a shared admin MCPConnectionConfig row and _db_mcp_server_to_api_mcp_server returns that row through auth_template.headers to any BASIC_ACCESS user. This issue is fixed in versions 3.1.10, 3.2.14, and 4.0.0.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
CVSS Score: 9.6

Product Status

Vendor onyx-dot-app
Product onyx
Versions
  • Version < 3.1.10 is affected
  • Version >= 3.2.0, < 3.2.14 is affected
  • Version >= 3.3.0-beta.0, < 4.0.0 is affected

References

Problem Types

  • CWE-200: Exposure of Sensitive Information to an Unauthorized Actor CWE
  • CWE-863: Incorrect Authorization CWE