CVE-2026-63263: Elastic Elasticsearch

Medium severity, CVSS 6.5. EPSS: 0.4% chance of exploitation in the next 30 days.

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.

Affected products

• Elastic Elasticsearch: from 8.0.0, before 8.19.19 (fixed in 8.19.19); from 9.0.0, before 9.3.8 (fixed in 9.3.8); from 9.4.0, before 9.4.4 (fixed in 9.4.4)

Published 2026-07-22. Last modified 2026-08-03.