EUVD-2026-21488

Apache Log4net's XmlLayout https://logging.apache.org/log4net/manual/configuration/layouts.htmllayout-list and XmlLayoutSchemaLog4J https://logging.apache.org/log4net/manual/configuration/layouts.htmllayout-list , in versions before 3.3.0, fail to sanitize characters forbidden by the XML 1.0...

Apache Log4j Core: Silent log event loss in XmlLayout due to unescaped XML 1.0 forbidden characters

Apache Log4j Core's XmlLayout, in versions up to and including 2.25.3, fails to sanitize characters forbidden by the XML 1.0 specification, producing invalid XML output whenever a log message or MDC value contains such characters. The impact depends on the StAX implementation in use: JRE built-in...