Vulnerability · Published Aug 13, 2026 · Assigned by elastic
CVE-2026-72678Memory Allocation with Excessive Size Value in Elasticsearch Leading to Denial of Service
Medium 6.5
In plain English
A medium-severity security flaw in Elasticsearch from Elastic. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 41% of all known vulnerabilities).
Official description
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 (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Elastic | Elasticsearch | 8.19.0 – through 8.19.199.4.0 – through 9.4.49.5.0 |
Weakness: CWE-789 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H