Description
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.
Published: 2026-08-13
Score: 6.5 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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Remediation

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History

Thu, 13 Aug 2026 19:30:00 +0000

Type Values Removed Values Added
Description 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.
Title Memory Allocation with Excessive Size Value in Elasticsearch Highlighting Leading to Denial of Service
Weaknesses CWE-789
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}


Subscriptions

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cve-icon MITRE

Status: PUBLISHED

Assigner: elastic

Published:

Updated: 2026-08-13T20:28:15.250Z

Reserved: 2026-08-10T11:17:35.480Z

Link: CVE-2026-72639

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-13T20:17:24.427

Modified: 2026-08-13T20:17:24.427

Link: CVE-2026-72639

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

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Weaknesses