Download latest patch from VMware ESXi 5.0.0
http://www.vmware.com/patchmgr/download.portal
for ESXi 5.0.0 latest patch (at time when writing this is) is
ESXi500-201510001 build number 3086167
filename ESXi500-201510001.zip
upload this file to ESXi datastore
put the host into Maintenance mode
enable SSH via vSphere client via configuration > Security Profile > Properties > SSH
Connect via SSH
Type this command for update: (you can add option –dry-run to perform a dry-run only)
esxcli software vib update -d /vmfs/volumes/<your_datastore>/ESXi500-201510001.zip
when update is finished type reboot or reboot via vSphere client
after reboot you can check build number
esxcli system version get