Since yesterday you can download IBM Connections 4.0 CR3 fixpack from here.
The fix list is available via this link.
Update - 22-03-2013:
An additional fix(COMMON 18.104.22.168 CR3 - LO74465) has been published for CR3. So make sure you also download and install it as well (especially if you have clients accessing Connections 4 CR3 with IBM Notes 9 clients). I have updated the link above to include this as well.
Update - 28-03-2013:
Do not miss the necessary steps for upgrading the metrics database (starting with CR3) and homepage database (starting ith CR2)!