A few days ago, I downloaded all possible ESXi 6.5 patch and tested the upgrade procedure lab, At that time, the latest patch was VMware ESXi, 6.5.0, 7526125 (File name: ESXi650-201801001.zip). Today, I double check the available patches, I cannot find that patch any more.
Is it withdraw?
Yes it has been withdrawn.
From https://kb.vmware.com/s/article/52236
NOTE: VMware withdrew the patches associated with VMSA-2018-0004. For more information, see KB 52345 .
Below KB provides build numbers and versions of ESXi/ESX. you can bookmark below link for future reference to check vaild and latest build number released by Vmware .