This applies to non-default configurations in which a non-default Pattern Layout using either a Context Lookup, e.g. $${ctx:loginId}, or a Thread Context Map pattern (%X, %mdc, or %MDC). "Log4j 2. ...

They noted that only the Log4j-core JAR file is impacted by CVE-2021-45105. On Friday, security researchers online began tweeting about potential issues with 2.16.0, with some identifying the ...