Where do I find MySQL security patch/update Oracle just released in April, 2018? (2 replies)

I was trying to find the patch/update Oracle just released in April, 2018, for example, in advisory http://www.oracle.com/technetwork/security-advisory/cpuapr2018-3678067.html#AppendixMSQL, CVE-2018-2761 is affecting 5.7.21 and prior, which means I have to apply the patch to MySQL 5.7.21, however, I couldn't find it.

It seems I have to have Oracle support account to get it but when I try to register, I was told I needed to provide a "support identifier", which I don't have since MySQL community server is a free product...

Can anybody help me with what I should do?

Thanks.