Description

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.

Classification

CVE ID: CVE-2025-37730

CVSS Base Severity: MEDIUM

CVSS Base Score: 6.5

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N

Affected Products

Vendor: Elastic

Product: Logstash

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.02% (probability of being exploited)

EPSS Percentile: 3.36% (scored less or equal to compared to others)

EPSS Date: 2025-06-04 (when was this score calculated)

Stakeholder-Specific Vulnerability Categorization (SSVC)

SSVC Exploitation: none

SSVC Technical Impact: partial

SSVC Automatable: false

References

https://nvd.nist.gov/vuln/detail/CVE-2025-37730
https://discuss.elastic.co/t/logstash-8-17-6-8-18-1-and-9-0-1-security-update-esa-2025-08/377869

Timeline