CVE-2020-15813: Graylog before 3.3.3 lacks SSL Certificate Validation for LDAP servers. It allows use of an external user/group database stored in LDAP. The connectio...

Description

Graylog before 3.3.3 lacks SSL Certificate Validation for LDAP servers. It allows use of an external user/group database stored in LDAP. The connection configuration allows the usage of unencrypted, SSL- or TLS-secured connections. Unfortunately, the Graylog client code (in all versions that support LDAP) does not implement proper certificate validation (regardless of whether the "Allow self-signed certificates" option is used). Therefore, any attacker with the ability to intercept network traffic between a Graylog server and an LDAP server is able to redirect traffic to a different LDAP server (unnoticed by the Graylog server due to the lack of certificate validation), effectively bypassing Graylog's authentication mechanism.

Metrics

CVSS 3.1

8.1/10

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

EPSS Probability

0.78%

51.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-295

Affected Software

Vendor	Product	Versions
Graylog	Graylog	< 3.3.3

References

https://github.com/Graylog2/graylog2-server/issues/5906Third Party Advisory
https://github.com/Graylog2/graylog2-server/issues/5906Third Party Advisory

Timeline

Published: Jul 17, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-15813?

Graylog before 3.3.3 lacks SSL Certificate Validation for LDAP servers. It allows use of an external user/group database stored in LDAP. The connection configuration allows the usage of unencrypted, SSL- or TLS-secured connections. Unfortunately, the Graylog client code (in all versions that support LDAP) does not implement proper certificate validation (regardless of whether the "Allow self-signed certificates" option is used). Therefore, any attacker with the ability to intercept network traffic between a Graylog server and an LDAP server is able to redirect traffic to a different LDAP server (unnoticed by the Graylog server due to the lack of certificate validation), effectively bypassing Graylog's authentication mechanism.

How severe is CVE-2020-15813?

CVE-2020-15813 has a CVSS score of 8.1/10 (HIGH severity). The EPSS model estimates a 0.78% probability of exploitation in the next 30 days.

How do I fix CVE-2020-15813?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.