CVE-2026-33465 in Kibana
Summary
by MITRE • 09/01/2026
Allocation of Resources Without Limits or Throttling (CWE-770) in Kibana can lead to a denial of service via Excessive Allocation (CAPEC-130). An authenticated user with low-level permissions could submit a specially crafted request that causes excessive resource consumption, which may render Kibana unavailable.
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Analysis
by VulDB Data Team • 09/01/2026
The vulnerability identified as CWE-770 represents a critical flaw in the resource management logic of Kibana, specifically concerning how the application handles input from authenticated users with low-level permissions. This issue stems from an architectural oversight where specific API endpoints or query mechanisms do not enforce strict limits on computational resources such as CPU cycles, memory allocation, or database connection pools. In a typical secure implementation, any user interaction that triggers complex data aggregation, search operations, or visualization rendering should be subject to throttling algorithms and resource caps to prevent single requests from monopolizing system capacity. However, in this vulnerable state, the application fails to validate the complexity of incoming queries against available resources, allowing an attacker to exploit this lack of control through excessive allocation techniques as defined by CAPEC-130.
From a technical perspective, an authenticated user with minimal privileges can craft specific requests that trigger deep recursive operations or massive data scans within Elasticsearch backend systems. These crafted payloads are designed to maximize the consumption of heap memory and processing time without triggering standard authentication or authorization checks because the permissions required are already granted. The absence of rate limiting means there is no mechanism to slow down these resource-intensive operations, nor is there a hard cap on the size of results returned or the depth of aggregation pipelines executed. This allows the malicious request to consume disproportionate amounts of server resources relative to its privilege level, effectively bypassing the principle of least privilege in terms of operational impact rather than access control.
The operational impact of this vulnerability is severe and directly correlates with a denial of service condition for Kibana instances. When multiple such requests are submitted concurrently or even by a single persistent user over time, the server's available memory may be exhausted, leading to Java Virtual Machine crashes or out-of-memory errors that halt all processing capabilities. Alternatively, excessive CPU consumption can cause latency spikes so significant that legitimate users experience timeouts and inability to access dashboards or visualizations. This degradation of service affects not only the specific instance under attack but potentially impacts other tenants in multi-tenant deployments if resource isolation is insufficient. The availability of Kibana as a monitoring and analytics platform is thus compromised, leading to potential business disruption for organizations relying on real-time data visibility.
Mitigation strategies must focus on implementing robust input validation and resource governance mechanisms at both the application layer and infrastructure level. Administrators should immediately apply vendor-provided patches that introduce stricter query complexity limits and enforce throttling policies for all authenticated endpoints. It is also advisable to configure Elasticsearch cluster settings to limit shard sizes and disable expensive aggregations by default unless explicitly required by specific business use cases. Additionally, deploying a Web Application Firewall with rules capable of detecting anomalous request patterns can provide an additional layer of defense against excessive allocation attacks. Regular auditing of user permissions ensures that low-level accounts do not inadvertently possess access to high-cost API endpoints, thereby reducing the attack surface available for exploitation.