Description
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.
References8
- github.com/onyx-dot-app/onyx/commit/3f3d79d1a7722fdc84a1c61c8aa…
- github.com/onyx-dot-app/onyx/commit/4001cedd0a8968723bfe95dd188…
- github.com/onyx-dot-app/onyx/commit/b103937888fd5008067c2bb6eb6…
- github.com/onyx-dot-app/onyx/pull/11238
- github.com/onyx-dot-app/onyx/pull/11242
- github.com/onyx-dot-app/onyx/pull/11243
- github.com/onyx-dot-app/onyx/releases/tag/v4.0.0
- github.com/onyx-dot-app/onyx/security/advisories/GHSA-q62f-rv3h…
Metrics
- CVSS 3.1
-
9.6
CRITICAL
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N - EPSS — exploit probability
- 0% percentile: 43 · as of 11 November 2026
- CWE
- CWE-200CWE-863
Could this be exploited in your environment?
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