The Log4j 2.16 version is vulnerable to a High Severity Denial of Service attack with the impact being a full application crash, classified as CVE-2021-45105. A new fixed version (2.17.1) has been published by Apache, and it's recommended to upgrade to it. The vulnerability was discovered due to increased community exposure and rushed initial security fixes, which led to additional vectors and issues being identified. To mitigate the risk, users should prioritize upgrading to a minimum of 2.16.0 and then move to 2.17.1 if possible, or jump straight up to the latest version if they still have services yet to be upgraded. The community exposure and rushed fixes are expected to lead to more vulnerabilities in the near future, making it essential for users to be prepared with best practices such as scanning code daily, creating an SBOM, setting up automated CI/CD Pipelines, and practicing good open source hygiene.