The hotfixes can be downloaded from the TIBCO Support Customer Portal Web User Interface, using your username and password for the TIBCO Support web site.

Once logged in : 

select Hotfixes from the Downloads menu.
navigate to the hotfixes location:
For EBX : AvailableDownloads/EBX/6.2.3/hotfix-2
For EBX addons :  AvailableDownloads/EBX/6.2.3/hotfix-2/addons
The release notes and readme files have information about the issues that are addressed with these hotfixes.

EBX 6.2.3 HF-2 and EBX addons 6.2.3 HF-2 are now available for download.