← Back to Vulnerability Reports CVE Intelligence

CVE-2026-90898

See advisory•CRITICAL · CVSS 9.8•No exploitation reported

What is CVE-2026-90898?

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.

CVSS9.8 NVD 3.1
SeverityCRITICAL
ExploitationNo exploitation reported
EPSS2% · P83
Triage statusNo Known Exploit
ActionPatch within 48 hours
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWECWE-284
NVD published2026-09-14
NVD last modified2026-09-18

Timeline

  • 2026-09-14Published to the U.S. National Vulnerability Database (NVD)
  • 2026-09-18NVD record last updated
  • 2026-09-23First covered in a defend.network daily briefing

Affected product

See advisory

References

Referenced in our briefings & reports

Related vulnerabilities

Browse all tracked CVEs in the defend.network CVE database →

🤖 This CVE page is generated by defend.network from NVD, CISA KEV, EPSS, and our verified daily briefings. Severity and exploitation data come from official sources; always verify remediation steps against the official vendor advisory before acting in production.