CVE-2026-72686: Elastic Elasticsearch

Medium severity, CVSS 6.5. EPSS: 0.6% chance of exploitation in the next 30 days.

A flaw in Elasticsearch allows a low-privileged authenticated user to submit a single request containing a crafted user-supplied input. A specific internal component validates the input using a recursive routine and applies no bound to the length of the value being validated, so the validation causes the thread to exhaust its stack. The resulting fatal error is not handled by the surrounding execution paths and terminates the affected node process, producing a denial of service.

Affected products

• Elastic Elasticsearch: from 8.0.0, before 8.19.20 (fixed in 8.19.20); from 9.0.0, before 9.4.5 (fixed in 9.4.5); from 9.5.0, before 9.5.1 (fixed in 9.5.1)

Published 2026-08-13. Last modified 2026-09-01.