Summary: Improper validation of certificate with host mismatch in Log4j2 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.
Mitigation: Users should upgrade to Apache Log4j 2.13.2 which fixed this issue in LOG4J2-2819 by making SSL settings configurable for SMTPS mail sessions. As a workaround for previous releases, users can set the `mail.smtp.ssl.checkserveridentity` system property to `true` to enable SMTPS hostname verification for all SMTPS mail sessions. https://issues.apache.org/jira/browse/LOG4J2-2819 CVE Details: CWE: 297 CVSS: 3.7 (Low) CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N Affects: Apache Log4j <= 2.13.1 Fixed: Log4j 2.13.2 Reported by: Peter Stöckli <peter.stoc...@alphabot.com> -- Matt Sicker Secretary, Apache Software Foundation VP Logging Services, ASF