VULNERABILITY INTELLIGENCE
CVE-2026-90898
CVSS score9.8 CRITICAL
EPSS probability2.31%
CISA KEVNot currently listed
Published2026-09-14
Last modified2026-09-18
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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 classification
- reefs@jfrog.com: CWE-284