What is CVE-2026-72638?

CVE-2026-72638 is a medium-severity vulnerability in Elastic Elasticsearch, classified under Uncontrolled Recursion. CVSS score: 6.5/10. Published 2026-08-13.

How severe is CVE-2026-72638?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Elastic Elasticsearch

CVE-2026-72638

Uncontrolled Recursion (CWE-674) in Elasticsearch can lead to denial of service via Input Data Manipulation (CAPEC-153). An authenticated user holding only low-privileged index creation permissions can submit a single request containing a specially crafted, malformed custom analysis definition that is resolved recursively without a cycle or depth check, exhausting the thread stack and terminating the affected node.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Affected products

Elastic Elasticsearch — versions 8.0.0, 9.0.0

Weakness classification (CWE)

CWE-674 — Uncontrolled Recursion

References

security@elastic.co

Frequently asked questions

What is CVE-2026-72638?: CVE-2026-72638 is a medium-severity vulnerability in Elastic Elasticsearch, classified under Uncontrolled Recursion. CVSS score: 6.5/10. Published 2026-08-13.
How severe is CVE-2026-72638?: Medium severity. CVSS v3 base score is 6.5 out of 10.