CVE-2026-78603 in Kibana
Summary
by MITRE • 09/01/2026
Missing Authorization (CWE-862) in Kibana can lead to information disclosure via Exploiting Incorrectly Configured Access Control Security Levels (CAPEC-180). An authenticated user holding minimal Elasticsearch privileges could bypass Kibana feature authorization and space access controls, resulting in the unauthorized disclosure of Fleet deployment metadata from the default Kibana space.
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Analysis
by VulDB Data Team • 09/01/2026
The vulnerability identified as a Missing Authorization flaw within the Elastic Stack's Kibana component represents a critical failure in enforcing role-based access control mechanisms at the application layer. This issue is categorized under CWE-862, which denotes insufficient authorization checks that allow users to perform actions or access data beyond their assigned privileges. The specific attack vector leverages CAPEC-180, Exploiting Incorrectly Configured Access Control Security Levels, where an attacker manipulates API requests to bypass intended security boundaries. In this scenario, the core issue lies in Kibana's inability to properly validate whether a user with minimal Elasticsearch-level permissions should have access to specific high-sensitivity features within the Kibana interface, particularly those related to Fleet management and deployment metadata.
From an operational perspective, the flaw allows any authenticated user who possesses basic read privileges on Elasticsearch indices to circumvent Kibana's internal authorization logic. Normally, Kibana acts as a gatekeeper, ensuring that users can only interact with features and spaces for which they have been explicitly granted access by administrators. However, due to this misconfiguration or coding error, the application fails to enforce these space-level restrictions when processing certain API calls related to Fleet deployments. Consequently, an attacker does not need elevated privileges within Elasticsearch itself; standard user credentials are sufficient to trigger the vulnerability and retrieve sensitive configuration data that should remain isolated from general users.
The impact of this information disclosure is significant for organizations relying on centralized logging and security monitoring via Elastic Stack. The exposed data includes Fleet deployment metadata, which may contain details about agent configurations, server endpoints, API keys used by agents, and potentially other infrastructure topology information. This leakage provides an adversary with valuable intelligence regarding the target's architecture, facilitating further reconnaissance or more targeted attacks against specific components of the environment. By understanding how the monitoring stack is deployed and configured, attackers can identify potential weak points in network segmentation or authentication mechanisms associated with those monitored systems.
This vulnerability aligns closely with MITRE ATT&CK techniques related to Discovery, specifically T1087 Account Discovery and potentially T1592 Gather Victim Host Information if the metadata reveals host-specific details. The exploitation path demonstrates how application-layer logic flaws can undermine underlying database security models, highlighting that securing Elasticsearch indices alone is insufficient when the front-end application does not strictly enforce its own access policies. Organizations must recognize that authentication at one layer does not guarantee authorization compliance across all layers of a multi-tier architecture like Elastic Stack.
To mitigate this risk, immediate action should be taken to apply any available patches or updates released by Elastic Security for Kibana and Elasticsearch components affected by this CVE. Administrators should review their current user roles and permissions, ensuring that the principle of least privilege is strictly enforced not only at the Elasticsearch index level but also within Kibana's role configuration settings. It is advisable to audit existing users with minimal privileges to confirm they do not possess unintended access to sensitive spaces or features. Additionally, implementing network-level controls such as firewalls and reverse proxies can add a layer of defense by restricting direct API access from untrusted networks, although this should complement rather than replace proper application-level authorization fixes. Regular security assessments focusing on role-based access control configurations are recommended to prevent similar misconfigurations in the future.