CVE-2026-26939 in Kibana
Summary
by MITRE • 03/19/2026
Missing Authorization (CWE-862) in Kibana’s server-side Detection Rule Management can lead to Unauthorized Endpoint Response Action Configuration (host isolation, process termination, and process suspension) via CAPEC-1 (Accessing Functionality Not Properly Constrained by ACLs). This requires an authenticated attacker with rule management privileges.
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Analysis
by VulDB Data Team • 03/24/2026
The vulnerability identified as CVE-2026-26939 represents a critical authorization flaw within Kibana's server-side detection rule management system. This weakness falls under the Common Weakness Enumeration category 862, which specifically addresses missing authorization controls that allow unauthorized access to protected resources. The vulnerability manifests in Kibana's detection rule management capabilities, where attackers can manipulate endpoint response actions that are typically restricted to authorized personnel only. These response actions include critical operations such as host isolation, process termination, and process suspension, which can have severe operational consequences when executed without proper authorization. The flaw enables attackers to bypass access control mechanisms that should normally prevent unauthorized users from configuring these sensitive endpoint actions.
The technical exploitation of this vulnerability requires an authenticated attacker who already possesses rule management privileges within the Kibana environment. This prerequisite aligns with the CAPEC-1 attack pattern, which describes accessing functionality not properly constrained by access control lists. The attacker leverages their existing authenticated session and rule management permissions to configure endpoint response actions that should normally be restricted to administrators or security operations personnel. This represents a privilege escalation scenario where the attacker can expand their control over the system's security operations beyond their intended authorization scope. The vulnerability essentially allows for a lateral movement attack pattern where an attacker with basic rule management access can elevate their capabilities to perform critical security operations that should require higher-level administrative privileges.
The operational impact of this vulnerability extends beyond simple unauthorized access to potentially compromising the entire security infrastructure of an organization. When an attacker can configure host isolation actions, they gain the ability to disconnect critical systems from the network, effectively creating a denial of service condition that can disrupt business operations. Process termination and suspension capabilities provide attackers with the means to disable security monitoring processes, endpoint protection services, or other critical system components. These actions directly violate the principle of least privilege and can enable attackers to systematically weaken an organization's security posture. The vulnerability creates a pathway for attackers to undermine the integrity of the security monitoring system itself, potentially allowing them to evade detection while executing their malicious activities.
Organizations should implement multiple layers of defense to mitigate this vulnerability, starting with immediate patching of affected Kibana versions and ensuring proper access control configurations. The principle of least privilege must be strictly enforced, with rule management permissions carefully reviewed and limited to only essential personnel. Network segmentation and monitoring of rule management activities should be implemented to detect unauthorized configuration changes. Security teams should also establish automated alerts for critical endpoint response actions and maintain detailed audit trails of all rule modifications. From a compliance perspective, this vulnerability directly impacts the security controls outlined in frameworks such as NIST SP 800-53 and ISO 27001, where proper authorization and access control are fundamental requirements. The vulnerability also maps to several ATT&CK techniques including T1078 for valid accounts and T1566 for credential harvesting, as attackers may exploit this weakness to gain broader system access and maintain persistence within the environment.