CVE-2026-66797
Description
A flaw was found in the cluster-backup-operator. An attacker with write access to the backup storage location or the ability to create a Velero Backup object can inject malicious Role-Based Access Control (RBAC) resources into a backup. When this tampered backup is restored, the operator processes the malicious content, leading to a privilege escalation from backup-namespace-admin to hub cluster-admin. This allows the attacker to gain administrative control over the entire cluster.
Statement
Important: The cluster-backup-operator in Red Hat Advanced Cluster Management for Kubernetes is vulnerable to privilege escalation. An attacker with write access to the backup storage location or the ability to create Velero Backup objects can inject malicious RBAC configurations into a backup. During a restore operation, the operator will process this tampered content, granting the attacker hub cluster-admin privileges. This is considered Important due to the complete compromise of the hub cluster's administrative control.
Mitigation
Restrict access to the backup storage location (e.g., S3 bucket) to authorized personnel only. Implement strict Role-Based Access Control (RBAC) to limit which users or service accounts can create Velero Backup objects within the open-cluster-management-backup namespace. This prevents an attacker from injecting malicious ClusterRoleBindings into backups or referencing untrusted backup objects. Ensure that only trusted and verified backups are used for restore operations.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.5 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | High | N/A | N/A |
| Privileges Required | Low | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Changed | N/A | N/A |
| Confidentiality | High | N/A | N/A |
| Integrity Impact | High | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
Red Hat CVSS v3 Score Explanation
AC:H — requires backup storage tampering or direct Velero Backup creation, not just Restore CR authoring. S:C — escalation from backup-namespace scope to hub cluster-admin.
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data; Read Files or Directories
An attacker could read sensitive data, either by reading the data directly from a data store that is not restricted, or by accessing insufficiently-protected, privileged functionality to read the data.
Integrity
Technical Impact: Modify Application Data; Modify Files or Directories
An attacker could modify sensitive data, either by writing the data directly to a data store that is not restricted, or by accessing insufficiently-protected, privileged functionality to write the data.
Access Control
Technical Impact: Gain Privileges or Assume Identity; Bypass Protection Mechanism
An attacker could gain privileges by modifying or reading critical data directly, or by accessing privileged functionality.
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
An attacker could gain unauthorized access to resources on the system and excessively consume those resources, leading to a denial of service.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
