In Logstash versions after 6.4.0 and before 6.8.15 and 7.12.0 a TLS certificate validation flaw was found in the monitoring feature.

published 2021-05-13 5 y ago modified 2026-09-08 2 mo ago also BIT-logstash-2021-22138 , EUVD-2021-9289

cvss: 3.7; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits: 0; none known

In Logstash versions after 6.4.0 and before 6.8.15 and 7.12.0 a TLS certificate validation flaw was found in the monitoring feature. When specifying a trusted server CA certificate Logstash would not properly verify the certificate returned by the monitoring server. This could result in a man in the middle style attack against the Logstash monitoring data.

Patch / fix

fixed in 2

bitnami logstash 6.8.15, 7.12.0
elastic logstash 6.8.15, 7.12.0

Exploit prediction

0.46% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	3.7	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
NVD	2.0	4.3	AV:N/AC:M/Au:N/C:P/I:N/A:N
OSV	3.1	3.7	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected packages

ecosystem	package	affected	fixed in
bitnami	logstash	>=6.4.0, <6.8.15 >=7.0.0, <7.12.0	6.8.15 7.12.0

Affected products

Elastic Elasticsearch

Classification

Weakness

CWE-295 Improper Certificate Validation

References

discuss.elastic.co /t/elastic-stack-7-12-0-and-6-8-15-security-update/268125
vendor-advisory, advisory
security.netapp.com /advisory/ntap-20210629-0001/
third-party-advisory, advisory
nvd.nist.gov /vuln/detail/CVE-2021-22138
web

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary