CVE Watchtower


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CVE-2026-90898NVD

Vulnerability Summary

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.
Severity Level
CRITICAL(9.8)
Published Date
Sep 14, 2026
Last Modified
Sep 14, 2026
Exploitation Status
No confirmed exploitation yet
EPSS Score (30-Day)
Data Pending
Root Weakness (CWE)
N/A
CVSS v3.1 Base Metrics
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh