CVE-2026-66792 in Multicluster Global Hub
Summary
by MITRE • 08/17/2026
A flaw was found in the multicloud-operators-subscription component. This vulnerability allows a user on a managed cluster to escalate their privileges by creating a Subscription with specific, crafted annotations. Successful exploitation grants the attacker the ability to deploy resources into any namespace with the elevated permissions of the controller's Service Account, potentially leading to unauthorized access and control over cluster resources.
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Analysis
by VulDB Data Team • 08/17/2026
The vulnerability identified in the multicloud-operators-subscription component represents a critical privilege escalation flaw within managed Kubernetes environments that utilize multi-cluster management frameworks. This issue stems from an insufficient validation mechanism when processing Subscription objects, specifically regarding how annotations are parsed and utilized by the controller logic. In typical operations, subscriptions define which applications or operators should be deployed to specific clusters based on predefined configurations. However, due to a logical error in handling crafted annotation values, an attacker with access to create subscription resources can manipulate this process to bypass intended namespace restrictions. The core technical flaw lies in the failure of the controller to strictly enforce scope boundaries when interpreting these annotations, allowing input that tricks the system into executing actions under the context of the highly privileged Service Account associated with the operator itself rather than limiting execution to the permissions granted by the user's own role bindings.
From a technical perspective, this vulnerability is classified as an insecure privilege escalation vector where untrusted input directly influences security-critical decisions within the application logic. The attacker exploits this by constructing a Subscription resource containing specific annotations that are not properly sanitized or validated against expected formats and scopes. When the multicloud-operators-subscription controller processes this malformed object, it incorrectly assumes elevated privileges based on these crafted inputs. This allows the deployment of arbitrary resources into any namespace within the managed cluster, regardless of whether the attacking user has permissions for those namespaces in their original role configuration. The operational impact is severe, as it effectively grants full control over the targeted Kubernetes cluster to anyone who can create subscription objects, which may be a relatively low-privilege action depending on the specific RBAC policies in place.
This vulnerability aligns with CWE-269, Improper Privilege Management, and specifically relates to CWE-732, Incorrect Permission Assignment for Critical Resource, as it involves misconfiguration of access controls that allow unauthorized elevation. In terms of the MITRE ATT&CK framework, this behavior corresponds to T1078, Valid Accounts, where an attacker uses legitimate credentials or permissions to gain higher-level access, and potentially T1543, Create or Modify System Process, if the deployed resources include persistent backdoors or malicious workloads. The ability to deploy into any namespace means that attackers can install monitoring tools for data exfiltration, create new administrative accounts, or compromise sensitive applications running in other namespaces, leading to a complete breach of cluster integrity and confidentiality.
Mitigation strategies must focus on immediate remediation of the underlying code logic within the multicloud-operators-subscription component. Developers should implement strict validation rules that ensure annotations are checked against an allowlist of expected values and formats before they influence controller behavior. It is crucial to enforce least privilege principles by ensuring that subscription controllers do not rely solely on user-provided metadata for determining execution context but instead strictly adhere to the namespace-scoped permissions defined in the Service Account bindings. Additionally, organizations should audit existing RBAC policies to ensure that the ability to create Subscription objects is restricted to trusted administrators only until a patch is applied. Regular security assessments and static code analysis focused on permission handling logic can help identify similar flaws before they are exploited in production environments.