CVE-2026-78591 in Kibana
Summary
by MITRE • 09/02/2026
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') (CWE-22) in the Kibana Fleet feature can lead to the unauthorized deletion of resources via Path Traversal (CAPEC-126). A low-privileged user could cause a subsequent action taken by a higher-privileged user in the Fleet administration interface to act on an unintended target, resulting in the deletion of resources including accounts with elevated privileges.
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Analysis
by VulDB Data Team • 09/02/2026
The vulnerability identified as CWE-22 represents a critical flaw within the Kibana Fleet feature, specifically manifesting as an improper limitation of pathname access relative to restricted directories. This technical deficiency allows for path traversal attacks, categorized under CAPEC-126, where an attacker manipulates input variables containing sequences such as dot-dot-slash or encoded equivalents to escape the intended directory scope. In the context of Kibana Fleet, which manages agent configurations and policies across a distributed environment, this flaw is particularly dangerous because it undermines the fundamental security boundary that separates user-managed resources from system-critical infrastructure components. The root cause lies in insufficient validation or sanitization of file paths provided by users during configuration updates or resource management operations, allowing maliciously crafted inputs to reference files outside the designated safe directory structure.
From an operational perspective, this vulnerability enables a low-privileged user to influence actions that are subsequently executed by higher-privileged administrators through the Fleet administration interface. This scenario describes a classic case of insecure direct object references combined with path traversal, where the attacker does not necessarily need elevated privileges themselves but can trick privileged processes into acting on unintended targets. By injecting maliciously constructed paths, an attacker can cause the system to interact with sensitive configuration files or internal resources that are normally protected from lower-level access. The immediate consequence of this exploitation is the unauthorized deletion of critical resources managed by Fleet. This includes not only standard agent configurations but also accounts and policies associated with elevated privileges, effectively compromising the integrity and availability of the entire monitoring infrastructure.
The impact extends beyond simple data loss to a significant degradation of security posture within the organization. The ability for a low-privileged user to trigger the deletion of high-privilege accounts means that an attacker can systematically dismantle the administrative controls required to manage endpoints securely. This aligns with ATT&CK techniques related to Defense Evasion and Impact, specifically those involving resource hijacking or destruction. By removing these critical components, the attacker disrupts visibility into endpoint activities, hinders incident response capabilities, and potentially creates backdoors by forcing administrators to recreate configurations without proper security hardening measures during the restoration process. The lack of strict input validation allows this attack vector to bypass standard access controls that rely on directory boundaries for enforcement.
Mitigation strategies must focus on implementing robust input validation and enforcing strict path canonicalization before any file system operations are performed. Developers should ensure that all user-supplied paths are resolved to their absolute forms and verified against a whitelist of allowed directories, rejecting any request that attempts to traverse outside the permitted scope using standard directory traversal sequences or encoded variations. Additionally, applying principle of least privilege principles within the application logic can limit the damage even if an exploit occurs by restricting which resources lower-privileged users can reference directly. Regular security audits and static code analysis focused on file system interactions are essential to identify similar flaws in other modules. Organizations should also consider deploying web application firewalls with rules specifically tuned to detect path traversal patterns as a temporary compensating control while patches are being developed and deployed.