CVE-2026-72666 in Kibana
Summary
by MITRE • 08/13/2026
Authorization Bypass Through User-Controlled Key (CWE-639) in Kibana can lead to unauthorized query execution against Elastic Agents that are assigned to a Kibana space the requesting user has no access to, via Accessing Functionality Not Properly Constrained by ACLs (CAPEC-1). A user who is authorized to run Osquery live queries in one space can have a query carried out on hosts belonging to another space, resulting in disclosure of information from those hosts to the Osquery results data stream.
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Analysis
by VulDB Data Team • 08/13/2026
This vulnerability represents a critical authorization bypass flaw classified as CWE-639 that affects the Kibana security platform within the Elastic stack ecosystem. The weakness occurs when user-controlled keys are improperly validated during access control decisions, allowing malicious actors to circumvent established security boundaries and execute unauthorized operations against systems they should not have access to.
The technical implementation of this vulnerability stems from inadequate validation of user permissions when processing Osquery queries within Kibana's multi-tenant architecture. When a user with legitimate access to run live Osquery queries in one Kibana space attempts to execute a query against hosts belonging to another space, the system fails to properly enforce access control lists that should normally prevent such cross-space operations. This misconfiguration creates an attack surface where unauthorized data exfiltration becomes possible through the Osquery results data stream.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables potential information disclosure attacks that can compromise sensitive data from systems belonging to other users or teams within the same Elastic infrastructure. Attackers can leverage this flaw to gather intelligence about hosts and systems they shouldn't be able to access, potentially leading to further exploitation opportunities and lateral movement within the network. The vulnerability particularly affects environments where multiple teams or departments share the same Kibana instance but require isolated operational boundaries.
This specific weakness maps directly to CAPEC-1, which describes access control bypasses through improperly constrained functionality. The attack vector exploits the fundamental principle of least privilege by allowing users to access resources beyond their designated permissions. Organizations using Elastic stack solutions should implement immediate mitigations including strict enforcement of access control policies, regular audit of user permissions, and monitoring for unusual query patterns that might indicate exploitation attempts.
The vulnerability highlights the importance of proper input validation and access control implementation in multi-tenant systems, aligning with security best practices outlined in NIST SP 800-53 and ISO/IEC 27001 frameworks. Organizations should also consider implementing additional monitoring controls around Osquery query execution and data access patterns to detect potential exploitation attempts. The flaw underscores the critical need for comprehensive security testing of access control mechanisms, particularly in distributed systems where multiple users interact with shared resources through web-based interfaces.
Security teams must prioritize patching this vulnerability as soon as vendor releases are available, while also conducting thorough assessments of their existing access control configurations to ensure proper isolation between different Kibana spaces. The mitigation strategy should include both immediate technical fixes and long-term architectural improvements to prevent similar authorization bypass scenarios from occurring in other components of the Elastic stack or similar multi-tenant platforms.