Vulnerability in Elastic Elasticsearch

CVE-2026-72636

Uncontrolled Recursion (CWE-674) in the Elasticsearch wildcard matching helper can lead to a denial of service via Excessive Allocation (CAPEC-130). The matcher used to resolve wildcard patterns against names is implemented recursively and had no bound on recursion depth or on the total number of match operations performed. A search request containing a wildcard pattern with a large number of wildcard groups, evaluated against a sufficiently long name, exhausts the thread stack. Elasticsearch treats a stack overflow as an unrecoverable condition and shuts the node down, so the request terminates the affected node rather than failing gracefully.

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

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-72636?
CVE-2026-72636 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-2026-72636?
Medium severity. CVSS v3 base score is 6.5 out of 10.