CVE-2025-37730: Elastic Logstash

Medium severity, CVSS 6.5. EPSS: 0.2% chance of exploitation in the next 30 days.

Improper certificate validation in Logstash's TCP output could lead to a man-in-the-middle (MitM) attack in “client” mode, as hostname verification in TCP output was not being performed when the ssl_verification_mode => full was set.

Affected products

• Elastic Logstash: from 8.0.0, before 8.17.6 (fixed in 8.17.6); from 8.18.0, before 8.18.1 (fixed in 8.18.1); from 9.0.0, before 9.0.1 (fixed in 9.0.1)

Published 2025-05-06. Last modified 2026-06-17.