Log in Start free

Vulnerability · Published Aug 17, 2026 · Assigned by GitHub_M

CVE-2026-71424Onyx: Cross-user OAuth-token leak via /api/mcp/servers* for per-user MCP servers

Critical 9.6

In plain English

A critical-severity information exposure in onyx from onyx-dot-app. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities).

Severity (CVSS 3.1)9.6Critical
Exploit odds (30 days)0.5%top 57.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

VendorProductVersions
onyx-dot-app onyx < 3.1.10>= 3.2.0, < 3.2.14>= 3.3.0-beta.0, < 4.0.0

Weakness: CWE-200, CWE-863 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N

References