CVEvulnerability

CVE-2026-90898

9.8 CRITICAL Published 2026-09-14 Modified 2026-09-18 Official page ↗

Status: Awaiting Analysis
Published: 2026-09-14
Last modified: 2026-09-18
Assigner: [email protected]
CVSS 3.1 ([email protected]): 9.8 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weaknesses: CWE-284, CWE-306

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.

Weakness · CWE (2)

CWE-284 Improper Access Control weakness
CWE-306 Missing Authentication for Critical Functionality weakness

References

https://github.com/maximhq/bifrost github.com
https://github.com/maximhq/bifrost/commit/12e170352bd25eab1ae9ba16611f1797d1fd8fdc github.com
https://github.com/maximhq/bifrost/pull/6757 github.com
https://github.com/maximhq/bifrost/releases/tag/transports/v2.1.0 github.com

CVE-2026-90898

Description

Related

Weakness · CWE (2)

References