Does that mean it's only vulnerable if JMSAppender is used otherwise not? Which should at least be a rarer use case.
Re:Log4j RCE Found
by philipwhiuk on Saturday December 11, 2021 @09:39AM
(#29521151)
Log4J 1 is only vulnerable for JMS
Log4J 2 is vulnerable < 2.15.0. There are mitigations for > 2.10.0 and > 2.7.0
The comment you cited is referring to the option to disable the vulnerable feature, not the vulnerable feature itself.
Per https://github.com/apache/logging-log4j2/pull/608#issuecomme... even log4j 1.x is vulnerable.