Inefficient Regular Expression Vulnerability in Elasticsearch by Elastic
CVE-2026-102408

4.3MEDIUM

Key Information:

Vendor

Elastic
Status
Elastic
Vendor
CVE Published:
6 October 2026

What is CVE-2026-102408?

An inefficiency in regular expression handling within Elasticsearch can lead to denial of service through recursive chunking strategies in its ES|QL CHUNK function. This issue allows authenticated users to submit crafted regular expressions that incur significant CPU usage, leading to degraded query throughput in multi-tenant environments. While the cluster remains operational, the performance impact can hinder user experience and operational efficiency.

Affected Version(s)

Elasticsearch 8.19.0 <= 8.19.21

Elasticsearch 9.1.0 <= 9.3.8

Elasticsearch 9.4.0 <= 9.4.7

References

https://discuss.elastic.co/t/elasticsearch-8-19-22-9-4-8-...

CVSS V3.1

Score:
4.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.