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VULNERABILITIES

CVE-2026-90898 Details

Description

Bifrost registers MCP clients through its management API. A stdio client is a command plus args. Bifrost starts that program in the gateway the moment the client is added. No MCP handshake required. The default is governance.auth_config.is_enabled=false. Auth off means every caller is a local admin. One unauthenticated POST /api/mcp/client is enough to run a program as the Bifrost process user (appuser on the official image).  transports/v2.1.0 refuses an unauthenticated stdio registration with 403. transports/v2.0.0 still allows it.

Metrics

CVSS 3.x Severity and Vector Strings:

CNA: [email protected]CVSS-B:9.8 CRITICALVector:CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

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URLSource(s)Tag(s)
https://github.com/maximhq/bifrost [email protected]
https://github.com/maximhq/bifrost/commit/12e170352bd25eab1ae9ba16611f1797d1fd8fdc [email protected]
https://github.com/maximhq/bifrost/pull/6757 [email protected]
https://github.com/maximhq/bifrost/releases/tag/transports/v2.1.0 [email protected]

Weakness Enumeration

CWE-IDCWE NameSource
CWE-284Improper Access Control[email protected]
CWE-306Missing Authentication for Critical Function[email protected]

Affected Products

No affected product data is available for this CVE.

Change History

2 change records found show changes

QUICK INFO

CVE Dictionary Entry:
CVE-2026-90898
NVD Published Date:
Sep 14, 2026
NVD Last Modified:
Sep 18, 2026
Source:
[email protected]
CVE-2026-90898 Details - Not Deferred