CVE-2026-0531 is a vulnerability classified under CWE-770 (Allocation of Resources Without Limits or Throttling) found in Elastic Kibana Fleet. The flaw allows an attacker with viewer-level privileges—who normally has read-only access to agent policies—to craft bulk retrieval requests that trigger redundant database retrieval operations. These operations cause excessive memory allocation, rapidly consuming server resources until the Kibana server crashes and becomes unavailable to all users, effectively causing a denial-of-service (DoS) condition. The vulnerability affects multiple Kibana versions, including 7.10.0, 8.0.0, 9.0.0, and 9.2.0. Exploitation does not require user interaction but does require the attacker to have authenticated access with viewer privileges. The CVSS v3.1 base score is 6.5, reflecting a medium severity level, with the primary impact on availability (A:H), no impact on confidentiality or integrity, and low attack complexity (AC:L). No public exploits are currently known, but the vulnerability poses a risk to service continuity in environments where Kibana Fleet is used for monitoring and managing Elastic Agents. The root cause is the lack of throttling or limits on resource allocation during bulk retrieval requests, allowing resource exhaustion through repeated redundant queries.

For European organizations, the primary impact of CVE-2026-0531 is the potential for denial of service in Kibana Fleet environments. Kibana is widely used for log aggregation, monitoring, and analytics across various sectors including finance, telecommunications, government, and critical infrastructure. A successful exploitation could disrupt operational visibility and incident response capabilities, delaying detection and mitigation of other security incidents. This could lead to operational downtime, reduced productivity, and potential regulatory compliance issues, especially under GDPR where availability is a component of data protection. Organizations relying heavily on Kibana for real-time monitoring may experience significant business impact during outages. Additionally, the requirement for only viewer-level privileges means that insider threats or compromised low-privilege accounts could be leveraged to cause disruption. The lack of known exploits currently reduces immediate risk, but the medium severity and ease of exploitation warrant proactive mitigation.

1. Restrict assignment of the viewer role strictly to trusted users and regularly audit user privileges to ensure least privilege principles are enforced. 2. Implement network segmentation and access controls to limit who can reach Kibana Fleet endpoints, reducing exposure to potential attackers. 3. Monitor Kibana server resource utilization closely, setting alerts for unusual spikes in memory or CPU usage that could indicate exploitation attempts. 4. Apply rate limiting or throttling at the application or proxy level to prevent excessive bulk retrieval requests from overwhelming the system. 5. Keep Kibana and Elastic Stack components updated and apply security patches promptly once Elastic releases fixes for this vulnerability. 6. Consider deploying Web Application Firewalls (WAFs) or Intrusion Detection Systems (IDS) with custom rules to detect and block suspicious bulk retrieval request patterns. 7. Conduct regular security training for administrators and users with viewer privileges to raise awareness about the risks of privilege misuse. 8. Review and harden Kibana Fleet configurations to minimize unnecessary exposure of agent policies and sensitive endpoints.