Inefficient Regular Expression Complexity in Elasticsearch Leading to Denial of Service

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-102408
StatePUBLISHED
Assignerelastic
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-06 20:17:12 UTC
Updated2026-10-06 20:17:12 UTC
DescriptionInefficient Regular Expression Complexity (CWE-1333) in Elasticsearch can lead to denial of service via Regular Expression Exponential Blowup (CAPEC-492). The ES|QL CHUNK function's recursive chunking strategy accepts a list of user-supplied regular expressions used as text-splitting separators, without validating their computational complexity or bounding their execution time. An authenticated user with read access to any text-based index can submit a specially crafted regular expression that triggers catastrophic backtracking, consuming excessive CPU on Elasticsearch worker threads and degrading query throughput for other tenants on the affected node. The cluster does not crash as a result of this issue.

Risk And Classification

Primary CVSS: v3.1 4.3 MEDIUM from [email protected]

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

Problem Types: CWE-1333 | CWE-1333 CWE-1333 Inefficient Regular Expression Complexity

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary4.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
3.1CNACVSS4.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

CVSS v3.1 Breakdown

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

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Elastic Elasticsearch affected 8.19.0 8.19.21 semver Not specified
CNA Elastic Elasticsearch affected 9.1.0 9.3.8 semver Not specified
CNA Elastic Elasticsearch affected 9.4.0 9.4.7 semver Not specified
CNA Elastic Elasticsearch affected 9.5.0 9.5.4 semver Not specified

References

ReferenceSourceLinkTags
discuss.elastic.co/t/elasticsearch-8-19-22-9-4-8-and-9-5-5-security-update-esa-2... [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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