The Log4Shell vulnerability is a remote code execution (RCE) vulnerability that allows an attacker to execute arbitrary Java code on a target machine, exploiting the Java Naming and Directory Interface (JNDI) abstraction layer and the serialization of Java objects. Older versions of the Log4j library, which is widely used for logging, can be tricked into fetching and executing malicious code by referencing remote URLs, including those that reference serialized Java objects, known as RCE vulnerabilities. The exploit was first identified in 2016 but gained widespread attention recently due to its severity and potential impact on systems. To mitigate the vulnerability, developers are advised to update their Log4j library to version 2.17.1 or later, which includes security fixes for the identified vulnerabilities.