GHSA-h383-gmxw-35v2 Apache Log4j 1 to Log4j 2 bridge: silent log event loss in Log4j1XmlLayout due to unescaped XML 1.0 forbidden characters

• Maven org.apache.logging.log4j:log4j-core: >= 2.7, < 2.25.4 → fixed in 2.25.4 • Maven org.apache.logging.log4j:log4j-core: >= 3.0.0-beta1, <= 3.0.0-beta2 (no fix yet)

The `Log4j1XmlLayout` from the Apache Log4j 1-to-Log4j 2 bridge fails to escape characters forbidden by the XML 1.0 standard, producing malformed XML output. Conforming XML parsers are required to reject documents containing such characters with a fatal error, which may cause downstream log processing systems to drop or fail to index affected records. Two groups of users are affected: • Those using `Log4j1XmlLayout` directly in a Log4j Core 2 configuration file. • Those using the Log4j 1 configuration compatibility layer with `org.apache.log4j.xml.XMLLayout` specified as the layout class. Users are advised to upgrade to Apache Log4j 1-to-Log4j 2 bridge version `2.25.4`, which corrects this issue. > [!NOTE] > The Apache Log4j 1-to-Log4j 2 bridge is deprecated and will not be present in Log4j 3. Users are encouraged to consult the > Log4j 1 to Log4j 2 migration guide, and specifically the section on eliminating reliance on the bridge.