Which of the following steps should be taken before mitigating a vulnerability in a production server?

Before mitigating a vulnerability in a production server, it is crucial to refer to the change management policy. This policy outlines the procedures for implementing changes to production systems, ensuring that modifications are properly documented, tested, approved, and communicated to avoid unintended disruptions or new vulnerabilities. Escalating to the SDLC team is not the immediate next step; the SDLC team is involved in development, not necessarily the operational mitigation of a discovered vulnerability. Using the IR plan is for incident response, which occurs after a security incident, not typically before mitigating a known vulnerability. Performing a risk assessment to classify the vulnerability is a good practice, but the change management policy dictates the process for implementing the mitigation itself, making it the most direct and necessary step before proceeding with actual changes.