ESXi patches

VMware has released 2 updates to the ESXi Installable version you can download. be sure to run the VMware Infrastructure Update tool on your management computer on a regular basis.

VMware ESXi 3.5 Installable Update 3

Latest Version: 3.5 Update 3 | 2008/11/06 | Build: 123629

Or you can download the patches manually here and install them your self.  The ESX host will need to be rebooted to apply these patches.

ESXi 3.5 U3 Installable – Build 123629 (3.50 Upd3 17Nov2008)
ESXe350-200811401-O-SG – PATCH Build 130755 (02.Dec.2008)
ESXe350-200901401-O-SG – PATCH Build 143129 (30.Jan.2009)

http://download3.vmware.com/software/vi/ESXe350-200901401-O-SG.zip

Reference:

http://support.vmware.com/selfsupport/s3portal.portal?_nfpb=true&_windowLabel=SearchPatch&SearchPatch_actionOverride=%2Fportlets%2Fpatchupdate%2FfindPatchByProductVersion&_pageLabel=s3portal_pages_downloadPatch_page&version=3.5&product=ESXi%20(Embedded%20and%20Installable)