CVE-2026-26937 is a vulnerability classified under CWE-400 (Uncontrolled Resource Consumption) found in the Timelion component of Elastic Kibana versions 8.0.0 and 9.0.0. Timelion is a time series data visualization tool integrated into Kibana, which processes user-supplied input data to generate visual analytics. The vulnerability arises because the component does not properly limit or control resource usage when processing certain crafted input data, allowing an attacker to manipulate input parameters to cause excessive consumption of CPU, memory, or other system resources. This uncontrolled resource consumption can lead to denial of service (DoS), making the Kibana service unresponsive or crashing it entirely. The CVSS 3.1 base score is 6.5 (medium), with an attack vector of network (AV:N), low attack complexity (AC:L), requiring privileges (PR:L), no user interaction (UI:N), and impacting availability (A:H) only, with no confidentiality or integrity impact. The vulnerability does not require user interaction but does require the attacker to have low privileges on the system, which may be achievable through compromised credentials or insider threat. No public exploits have been reported yet, but the risk remains significant due to the potential impact on availability of Kibana dashboards and analytics services. The lack of patch links suggests that a fix may be pending or in development. The vulnerability is related to CAPEC-153, which involves input data manipulation to cause resource exhaustion. Organizations using Kibana for operational monitoring, security analytics, or business intelligence could face service interruptions if exploited.

The primary impact of CVE-2026-26937 is denial of service, which can disrupt the availability of Kibana dashboards and analytics services. This can affect operational monitoring, security incident detection, and business decision-making processes that rely on timely and accurate data visualization. In environments where Kibana is critical for security operations centers (SOCs) or real-time monitoring, this could delay incident response and increase risk exposure. The vulnerability does not compromise data confidentiality or integrity but can cause significant operational downtime and resource exhaustion on servers hosting Kibana. Organizations with multi-tenant Kibana deployments or those exposing Kibana to external networks are at higher risk. The requirement for low privileges reduces the attack surface but does not eliminate it, especially if credential compromise occurs. The absence of known exploits in the wild reduces immediate risk but does not preclude future exploitation. Overall, the impact is medium severity but can escalate if combined with other vulnerabilities or in high-dependency environments.

1. Restrict access to the Timelion feature in Kibana by limiting user privileges and roles to only trusted users who require it. 2. Implement network-level access controls such as firewalls or VPNs to restrict external access to Kibana interfaces. 3. Monitor resource usage on Kibana servers closely, setting alerts for unusual CPU or memory spikes that could indicate exploitation attempts. 4. Use rate limiting or input validation proxies to detect and block suspicious or malformed Timelion queries that could trigger resource exhaustion. 5. Regularly review and audit user privileges to ensure minimal necessary access is granted. 6. Stay informed about Elastic's security advisories and apply patches or updates promptly once they become available. 7. Consider isolating Kibana instances or running them in containerized environments with resource limits to contain potential DoS effects. 8. Employ logging and anomaly detection to identify potential exploitation attempts early. These steps go beyond generic advice by focusing on controlling Timelion access, proactive monitoring, and containment strategies.