CVE-2026-33459: Kibana DoS Vulnerability via Resource Abuse

CVE-2026-33459 Overview

An Uncontrolled Resource Consumption vulnerability (CWE-400) has been identified in Kibana that can lead to denial of service conditions. An authenticated user with access to the automatic import feature can submit specially crafted requests with excessively large input values. When multiple such requests are sent concurrently, the backend services become unstable, resulting in service disruption and deployment unavailability for all users.

Critical Impact

Authenticated attackers can cause complete service disruption for all Kibana users by exhausting backend resources through the automatic import feature.

Affected Products

• Kibana versions prior to 8.19.14
• Kibana versions prior to 9.2.8
• Kibana versions prior to 9.3.3

Discovery Timeline

• April 8, 2026 - CVE-2026-33459 published to NVD
• April 8, 2026 - Last updated in NVD database

Technical Details for CVE-2026-33459

Vulnerability Analysis

This vulnerability falls under CWE-400 (Uncontrolled Resource Consumption), a class of weaknesses where the software does not properly restrict the amount of resources consumed by an actor. In the context of Kibana, the automatic import feature lacks adequate input validation for request size parameters, allowing authenticated users to submit payloads with excessively large values.

The attack pattern aligns with CAPEC-130 (Excessive Allocation), where an adversary causes the target to allocate excessive resources to service a request, ultimately leading to resource exhaustion. When multiple malicious requests are processed concurrently, the cumulative resource consumption destabilizes backend services.

Root Cause

The root cause of this vulnerability is insufficient input validation and resource limiting within Kibana's automatic import feature. The application fails to enforce proper boundaries on input values, allowing users to specify excessively large allocation parameters. Additionally, there appears to be no rate limiting or concurrent request throttling mechanism in place to prevent resource exhaustion attacks.

Attack Vector

The attack is network-based and requires authentication with access to the automatic import feature. An attacker would craft HTTP requests containing abnormally large input values targeting the import functionality. By sending multiple concurrent requests, the attacker forces the backend to allocate excessive memory and processing resources, overwhelming the service and causing denial of service for all users.

The attack does not require user interaction and directly impacts service availability. While the attacker needs low-privilege authentication, the scope of impact extends to all users of the affected Kibana deployment.

Detection Methods for CVE-2026-33459

Indicators of Compromise

• Unusual spikes in memory consumption on Kibana backend services
• Multiple concurrent requests to the automatic import endpoint from the same authenticated user
• Abnormally large request payloads in web server access logs
• Service instability or crashes following import operations
• Error logs indicating resource exhaustion or allocation failures

Detection Strategies

• Monitor Kibana access logs for requests to the automatic import feature with unusually large payload sizes
• Implement alerting on sudden increases in memory usage or CPU consumption on Kibana nodes
• Track the rate of import requests per authenticated user to identify potential abuse patterns
• Configure application performance monitoring (APM) to detect response time degradation

Monitoring Recommendations

• Enable detailed logging for the automatic import feature to capture request parameters
• Set up resource utilization thresholds with automated alerting for Kibana services
• Implement network-level monitoring to detect concurrent request floods from single sources
• Review authentication logs for accounts making excessive use of the import functionality

How to Mitigate CVE-2026-33459

Immediate Actions Required

• Upgrade Kibana to patched versions: 8.19.14, 9.2.8, or 9.3.3 or later
• Review and restrict user access to the automatic import feature to only necessary personnel
• Implement rate limiting at the reverse proxy or load balancer level for import endpoints
• Monitor system resources closely until patches can be applied
• Consider temporarily disabling the automatic import feature if not critical to operations

Patch Information

Elastic has released security updates addressing this vulnerability. Patched versions include Kibana 8.19.14, 9.2.8, and 9.3.3. Organizations should apply the appropriate update based on their current version branch. For detailed patch information, refer to the Elastic Security Update ESA-2026-26.

Workarounds

• Implement request size limits at the web server or reverse proxy level to reject excessively large payloads
• Configure rate limiting to restrict the number of concurrent import requests per user
• Use network segmentation to limit access to Kibana's import functionality
• Temporarily revoke import feature access for non-essential users until patches are applied

# Example nginx rate limiting configuration for import endpoints
# Add to your nginx server block
limit_req_zone $binary_remote_addr zone=kibana_import:10m rate=5r/s;

location /api/fleet/epm/packages/_automatic_import {
    limit_req zone=kibana_import burst=10 nodelay;
    client_max_body_size 10m;
    proxy_pass http://kibana_backend;
}