CVE-2026-72678: Elastic Elasticsearch

Medium severity, CVSS 6.5. EPSS: 0.5% chance of exploitation in the next 30 days.

Elasticsearch does not validate a size value taken from a user-supplied input before that value is used to reserve memory for an internal data structure. An authenticated user holding only read privileges can submit a single small crafted request to a product API endpoint that causes the node to attempt an excessively large allocation. The resulting memory exhaustion raises a fatal error that terminates the Elasticsearch node process, causing a denial of service for the affected node and degrading cluster health. The defect is not volumetric, so a single request is sufficient regardless of the heap size configured on the target node.

Affected products

• Elastic Elasticsearch: from 8.19.0, before 8.19.20 (fixed in 8.19.20); from 9.4.0, before 9.4.5 (fixed in 9.4.5); from 9.5.0, before 9.5.1 (fixed in 9.5.1)

Published 2026-08-13. Last modified 2026-09-01.