Elasticsearch does not enforce an upper bound on a user-supplied count accepted by a search highlighting option, and the allocation derived from that count is not accounted against any circuit breaker. An authenticated user holding only read privileges on a single searchable index can submit one small search request that causes the node to reserve an excessively large internal data structure. The allocation occurs before the existing highlighting safety limits are evaluated, so memory exhaustion raises a fatal error that terminates the Elasticsearch node process. This results in a denial of service for the affected node and degrades cluster routing and health. The defect is not volumetric and does not depend on the size of the indexed data, so a single request is sufficient.

Uncontrolled Recursion (CWE-674) in Elasticsearch can lead to denial of service via Input Data Manipulation (CAPEC-153). An authenticated user holding only low-privileged index creation permissions can submit a single request containing a specially crafted, malformed custom analysis definition that is resolved recursively without a cycle or depth check, exhausting the thread stack and terminating the affected node.

A flaw in Elasticsearch allows a low-privileged authenticated user to submit a single request containing a crafted user-supplied input. A specific internal component validates the input using a recursive routine and applies no bound to the length of the value being validated, so the validation causes the thread to exhaust its stack. The resulting fatal error is not handled by the surrounding execution paths and terminates the affected node process, producing a denial of service.

A flaw in Elasticsearch allows a low-privileged authenticated user who can index documents to submit a single small document containing a crafted user-supplied input. Processing one such document occupies a worker thread from a bounded pool for a disproportionate amount of time, degrading the availability of indexing operations on the affected node.

Incorrect Authorization (CWE-863) in Elasticsearch can allow an authenticated user with limited index privileges to exploit insufficient authorization controls in the ingest simulation feature. By targeting indices they are not authorized to access directly, the user can cause those indices' configured ingest pipelines to execute and return their output, potentially disclosing data processed or enriched by those pipelines. Additionally, the same feature can be used to retrieve index mapping metadata for indices the user are not authorized to access directly.

Uncontrolled Resource Consumption (CWE-400) in Elasticsearch can lead to denial of service via Excessive Allocation (CAPEC-130). A user with search privileges can submit a specially crafted search request that causes a data node to exhaust available heap memory, resulting in node unavailability and cluster degradation. An attacker could leverage this vulnerability to cause cluster downtime requiring manual intervention to restore service.

Uncontrolled Resource Consumption (CWE-400) in Elasticsearch can lead to denial of service via Exponential Data Expansion (CAPEC-197). An authenticated user may submit a specially crafted query to the ES|QL engine that causes exponential CPU consumption during query evaluation. Because the resource exhaustion persists beyond query completion, repeated requests can fully exhaust the available query worker resources, rendering ES|QL queries unavailable until the node is restarted.