CVE-2026-90898

critical · 9.8

A public exploit / detection template exists

Weaponised detection is publicly available, which meaningfully raises real-world risk regardless of CVSS. nuclei-templates →

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.

9.8

CVSS

2.3%

EPSS (exploit prob.)

83rd

EPSS percentile

2026-09-14

Published

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Weaknesses

CWE-284CWE-306

References

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

Query this programmatically:

curl https://evil-db.io/api/v1/cve/CVE-2026-90898