The Apache Log4j vulnerability, dubbed "Log4Shell," is a critical Remote Code Execution (RCE) flaw in the widely used open-source logging tool that can be exploited by attackers to gain control over affected systems and services. The severity of this vulnerability has been rated as 10.0 Critical by key facts, with numerous platforms including Apple, Cloudflare, Twitter, and popular Java ecosystem products being affected. Observers consider it one of the worst vulnerabilities in years, combining a large attack surface, easy exploitation, hard-to-avoid dependencies, and extreme virality. Organizations are advised to take a continuous, platform-powered security testing approach to find and remediate vulnerabilities before they cause damage.