A security analyst is reviewing the latest vulnerability scan report for a web server following an incident. The
vulnerability report showed no concerning findings. The vulnerability that was used to exploit the server is
present in historical vulnerability scan reports, and a patch is available for the vulnerability. Which of the
following is the MOST likely cause?


A. Security patches failed to install due to a version incompatibility.
B. An adversary altered the vulnerability scan reports.
C. A zero-day vulnerability was used to exploit the web server.
D. The scan resulted in a false negative for the vulnerability.