What’s Vulnerable › Vulnerabilities
CVE-2026-72678: Memory Allocation with Excessive Size Value in Elasticsearch Leading to Denial of Service
- Severity: medium (CVSS 6.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.5% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-08-13 · updated 2026-09-01
- Weakness: CWE-789
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
- Elasticsearch: from 8.19.0 before 8.19.20; from 9.4.0 before 9.4.5; from 9.5.0 before 9.5.1 — fixed in 8.19.20, 9.4.5, 9.5.1
How to fix
Upgrade to a fixed version: Elasticsearch 8.19.20, 9.4.5, 9.5.1. Check the vendor advisory for mitigations.
References
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