CVE-2026-102408

Inefficient Regular Expression Complexity in Elasticsearch Leading to Denial of Service

Published Oct 6, 2026 CVSS 3.1 · 4.3 Medium EPSS < 1% KEV · Not listed
Description
Inefficient 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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
CPEs cpe:2.3:a:elastic:elasticsearch:*:*:*:*:*:*:*:*
Type Values Removed Values Added
First Time appeared Elastic
Elastic elasticsearch
Vendors & Products Elastic
Elastic elasticsearch
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Inefficient 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.
Title Inefficient Regular Expression Complexity in Elasticsearch Leading to Denial of Service
Weaknesses CWE-1333
References
Metrics cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
elastic
Published
Updated
Oct 6, 2026, 7:56 PM
Reserved
Sep 29, 2026, 2:06 AM
Status
Analyzed
Published
Oct 6, 2026, 8:17 PM
Modified
Oct 13, 2026, 6:48 PM
Severity
Moderate
Public date
Oct 6, 2026, 7:31 PM