The Log4j vulnerability
The Log4j vulnerability allows attackers to execute code remotely on a target computer, which could allow them to steal data, install malware or take control.
Log4j is a widely used software logging library for Java software which was recently found to have serious security issues. An attacker taking benefits of the vulnerability could potentially execute arbitrary, malicious code on an affected system.
A 0day (or zero-day vulnerability) is a security flaw that has not been publicly disclosed and for that a software remediation technique is not available.