CVE-2020-9488
log4j: improper validation of certificate with host mismatch in SMTP appender
Severity
LowRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · April 25, 2020
Updated · August 5, 2026
Description
Improper validation of certificate with host mismatch in Apache Log4j SMTP appender. This could allow an SMTPS connection to be intercepted by a man-in-the-middle attack which could leak any log messages sent through that appender. Fixed in Apache Log4j 2.12.3 and 2.13.1
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
Previous versions can set the system property mail.smtp.ssl.checkserveridentity to true to globally enable hostname verification for SMTPS connections.
CVSS / CWE
CVSS 3.1 · 3.7CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
CWE-295 · Improper Certificate Validation