CVE-2026-90898 Bifrost transports - Command Injection

Bifrost transports v2.0.0 contains a command injection caused by unauthenticated stdio client registration via POST /api/mcp/client, letting unauthenticated attackers execute arbitrary programs as the Bifrost process user, exploit requires authentication disabled.

CVSS base score 9.8 /10
Critical
CISA KEV
Not listed
Public exploit
Proof of concept available
Authentication
Not required
EPSS
2.31% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Command Injection
Impact
Remote Code Execution
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
14 September 2026
Updated
15 October 2026
Weakness
CWE-284

Vendor fix

Upgrade to transports v2.1.0 or later where unauthenticated stdio registration is blocked.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

← All CVEs