Auth bypass in Onyx-Dot-App Onyx

CVE-2026-71424

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.

Vulnerability class: Information Disclosure

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.6 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.005 (39.8th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 40th percentile — 39.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-71424: held from 0.003 to 0.005.

EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002

Affected products

  • Onyx-Dot-App Onyx — versions < 3.1.10, >= 3.2.0, < 3.2.14, >= 3.3.0-beta.0, < 4.0.0

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-71424?
CVE-2026-71424 is a critical-severity vulnerability in Onyx-Dot-App Onyx, classified under Information Disclosure. CVSS score: 9.6/10. Published 2026-08-17.
How severe is CVE-2026-71424?
Critical severity. CVSS v3 base score is 9.6 out of 10.