Nagios Vulnerability

Hi All,
Below vulnerability was detected on my Nagios server by Qualys. Please help me to fix it.
TCP Sequence Number Approximation Based Denial of Service (QID 82054) detected on Port 80 on my server.
Below vulnerability was detected on my Nagios server by Qualys. Please help me to fix it.
TCP Sequence Number Approximation Based Denial of Service (QID 82054) detected on Port 80 on my server.