CVE-2026-78155 in StackGres
Summary
by MITRE • 08/23/2026
privilege escalation in StackGres operator allows a low-privilege tenant who owns a database to gain administrator privileges
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Analysis
by VulDB Data Team • 08/23/2026
The vulnerability identified within the StackGres Kubernetes Operator represents a critical privilege escalation flaw that undermines the fundamental security boundaries of multi-tenant PostgreSQL deployments. This issue arises from insufficient access control mechanisms governing how tenants interact with the underlying operator resources and cluster configurations. In typical cloud-native database architectures, operators manage stateful sets, persistent volume claims, and configuration maps to maintain high availability and data integrity for managed databases. However, in this specific implementation, a low-privilege tenant who possesses ownership or write access to their designated database resource is able to manipulate operator-level settings that should be restricted to cluster administrators. This misconfiguration allows the tenant to alter critical parameters such as authentication methods, connection limits, or even inject custom configurations that affect the broader operational environment of the managed PostgreSQL instance.
From a technical perspective, this flaw stems from an improper validation of user permissions when processing requests directed at the operator's webhook endpoints or API server interactions. The operator fails to enforce strict separation between tenant-scoped resources and cluster-wide administrative controls. Consequently, a malicious actor with limited privileges can exploit these overly permissive rules to escalate their access level. By modifying specific configuration fields that are normally immutable by non-admin users, the attacker can effectively bypass authentication checks or gain control over database processes running under elevated system accounts. This capability transforms what should be an isolated tenant environment into one where lateral movement and privilege escalation become feasible, compromising the integrity of both the targeted database and potentially other databases hosted on the same cluster if shared resources are affected.
The operational impact of this vulnerability is severe, as it directly compromises confidentiality, integrity, and availability within the managed database service. An attacker who successfully exploits this flaw can extract sensitive data from the compromised database by altering connection parameters to allow unauthenticated access or by dumping configuration files that contain credentials stored in environment variables or secrets. Furthermore, the ability to modify operational settings may lead to denial of service conditions if the attacker configures resource limits incorrectly or triggers excessive logging and processing loads. In a multi-tenant SaaS context, this breach not only affects the immediate victim but also poses significant risks to other tenants sharing the infrastructure due to potential cross-tenant data leakage or disruption of services. The erosion of trust in the managed database service can have profound business implications, including regulatory non-compliance and loss of customer confidence.
To mitigate this risk, it is imperative that StackGres operators implement rigorous role-based access control (RBAC) policies that strictly delineate between tenant-level operations and cluster-administrator functions. Developers must ensure that webhook validations reject any attempts by low-privilege users to modify fields related to authentication mechanisms, security contexts, or operator-wide configurations. Additionally, adopting the principle of least privilege across all service accounts associated with the operator is essential. Security teams should also enable audit logging for all configuration changes and monitor for anomalous patterns indicative of privilege escalation attempts. Regular penetration testing focused on API endpoint permissions and resource boundary enforcement will help identify similar weaknesses before they can be exploited in production environments. Aligning these remediation steps with industry standards such as CWE-269, which addresses improper authorization, and ATT&CK techniques related to account manipulation and defense evasion, ensures a robust security posture against internal threats.