What is the CVSS score of CVE-2026-40213?

CVE-2026-40213 has a CVSS 3.1 base score of 7.4 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L. EPSS exploitation probability: 0.0%.

Which versions of OpenStack Cyborg are affected by CVE-2026-40213?

OpenStack Cyborg versions before 16.0.1 contain an authentication bypass allowing any user with valid credentials to reprogram FPGA hardware and execute privileged operations across compute…. A patch is available.

How to fix or mitigate CVE-2026-40213?

Within 24 hours: Inventory all OpenStack Cyborg deployments and document current versions; disable or isolate Cyborg API endpoints if versions are below 16.0.1. Within 7 days: Restrict network access to Cyborg agents to trusted administrative networks only; implement mandatory policy overrides in policy.json to explicitly deny non-admin API access. Within 30 days: Upgrade to OpenStack Cyborg 16.0.1 or later; validate policy enforcement post-upgrade with explicit role-based access control testing.

OpenStack Cyborg CVE-2026-40213

EUVD-2026-28455 HIGH

Incorrect Authorization (CWE-863)

2026-05-07 cve@mitre.org

GHSA-mm7j-mhhj-hj36

Authentication Bypass

7.4

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

7.4 HIGH

AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

Low

Lifecycle Timeline

Patch available

May 07, 2026 - 23:02 EUVD

Analysis Generated

May 07, 2026 - 22:30 vuln.today

CVE Published

May 07, 2026 - 22:16 nvd

HIGH 7.4

DescriptionCVE.org

OpenStack Cyborg before 16.0.1 uses rule:allow (check_str='@') as the default policy for multiple API endpoints. This unconditionally authorizes any request carrying a valid Keystone token regardless of roles, project membership, or scope. An authenticated user with zero role assignments can complete various actions such as reprogramming FPGA bitstreams on arbitrary compute nodes via agent RPC.

AnalysisAI

OpenStack Cyborg allows any authenticated user to reprogram FPGA bitstreams and execute privileged operations across arbitrary compute nodes due to unconditional authorization bypass in multiple API endpoints. Versions before 16.0.1 use rule:allow as the default policy, permitting any valid Keystone token holder-even users with zero role assignments-to perform administrative actions including FPGA reconfiguration via agent RPC. EPSS data not available, but the authentication bypass combined with scope change (CVSS S:C) and hardware manipulation capabilities represents significant risk in multi-tenant OpenStack deployments.

Technical ContextAI

OpenStack Cyborg is the lifecycle management service for hardware accelerators (FPGAs, GPUs, cryptographic accelerators) in OpenStack clouds. The vulnerability stems from CWE-863 (Incorrect Authorization) where the default policy engine configuration uses 'rule:allow' with check string '@' for multiple API endpoints. In OpenStack's policy framework, this pattern bypasses role-based access control (RBAC) entirely, treating any authenticated Keystone token as sufficient authorization regardless of project membership, domain scope, or assigned roles. The impact extends to agent RPC calls that control physical accelerator hardware, allowing unauthorized bitstream programming-essentially reprogramming the logic gates of FPGAs attached to compute nodes. This creates both a privilege escalation path and a potential hardware-level attack surface in Infrastructure-as-a-Service environments where accelerator resources should be strictly isolated between tenants.

RemediationAI

Upgrade OpenStack Cyborg to version 16.0.1 or later, which implements proper role-based access control policies replacing the unconditional rule:allow defaults. The fix restricts API endpoints to appropriate roles such as 'admin', 'service', or project-scoped member roles as documented in OpenStack's policy-in-code framework. For environments unable to upgrade immediately, implement compensating controls by manually editing Cyborg's policy.yaml or policy.json configuration file to replace '@' check strings with role-based rules such as 'role:admin' or 'role:service' for administrative endpoints-consult the upstream patch at Launchpad bug 2143263 for specific policy changes. This manual remediation requires Cyborg service restart and careful testing as overly restrictive policies may break legitimate accelerator provisioning workflows. Network-level mitigation is insufficient because the vulnerability is exploitable by any authenticated OpenStack user, including legitimate tenant accounts. Defense-in-depth measures include auditing Keystone token issuance logs for accounts with minimal role assignments making Cyborg API calls, and restricting Cyborg API endpoint network access to internal management networks only (though this does not prevent abuse by compromised tenant VMs with management network access). Full vendor details at https://bugs.launchpad.net/openstack-cyborg/+bug/2143263 and security mailing list discussion at https://www.openwall.com/lists/oss-security/2026/05/07/6.