Memory Allocation with Excessive Size Value in Elasticsearch Highlighting Leading to Denial of Service

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-72639
StatePUBLISHED
Assignerelastic
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-13 20:17:24 UTC
Updated2026-08-13 21:18:09 UTC
DescriptionElasticsearch 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.

Risk And Classification

Primary CVSS: v3.1 6.5 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS: 0.002890000 probability, percentile 0.214850000 (date 2026-08-16)

Problem Types: CWE-789 | CWE-789 CWE-789 Memory Allocation with Excessive Size Value

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
3.1CNACVSS6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Elastic Elasticsearch affected 8.19.0 8.19.19 semver Not specified
CNA Elastic Elasticsearch affected 9.3.0 9.5.0 semver Not specified

References

ReferenceSourceLinkTags
discuss.elastic.co/t/elasticsearch-8-19-20-9-4-5-9-5-1-security-update-esa-2026-... [email protected] discuss.elastic.co
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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