CVE-2026-71424CWE-200CWE-863broken-access-controlinformation-disclosure

CVE-2026-71424

Critical · published August 18, 2026

CVSS v3.1
9.6
EPSS
0%
Percentile
41.1
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
9.6 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
CVSS v4.0
Not supplied
EPSS
0.00488 · 41.1th percentile
Weaknesses
CWE-200 · Exposure of Sensitive Information to an Unauthorized Actor; CWE-863 · Incorrect Authorization
Published
2026-08-18T02:17Z
References (8)
https://github.com/onyx-dot-app/onyx/commit/3f3d79d1a7722fdc84a1c61c8aa830d890017e9e · [email protected]https://github.com/onyx-dot-app/onyx/commit/4001cedd0a8968723bfe95dd188914ed56777910 · [email protected]https://github.com/onyx-dot-app/onyx/commit/b103937888fd5008067c2bb6eb6e5424576394f2 · [email protected]https://github.com/onyx-dot-app/onyx/pull/11238 · [email protected]https://github.com/onyx-dot-app/onyx/pull/11242 · [email protected]https://github.com/onyx-dot-app/onyx/pull/11243 · [email protected]https://github.com/onyx-dot-app/onyx/releases/tag/v4.0.0 · [email protected]https://github.com/onyx-dot-app/onyx/security/advisories/GHSA-q62f-rv3h-f822 · [email protected]
EPSS history
Timeline
  • 17 AUG 21:28Z
    Onyx: Cross-user OAuth-token leak via /api/mcp/servers* for per-user MCP servers
    cvelistv5