It's a misconception installing the very latest release of the update for Kernel-Mode Drivers will solve it all.
It's a misconception any version of a
Windows update released after EOL is required to solve the issue. Also, KB4048970 has been superseded on January 9th.
You may be missing KB4011660 and KB4011659.
why has vista stopped automatic updates?
mostly true when installing Vista from scratch (a fresh or clean install of Vista) and
installing only the newest win32k.sys patch alone does not directly solve the WU problem. that still requires installing the other "Kernel" updates (updated advapi32.dll, gdi32.dll, NTOSKRNL, kernel32.dll, shell32.dll, user32.dll along with the Vista platform updates) before installing the newest win32k.sys patch.
KB4048970 has been superseded by
KB4056944.
I manually install the old Vista Updates using
LDRInstaller to install the LDR (or QFE) branch of the updates instead of the normal GDR branch.
It's too bad M$ did not bother updating the WU client for Vista like they did for Win7 with KB3172605 & Win8.1 with KB3172614. a newer WU agent/client app greater than v7.6.7600.256 would have been a more permanent solution to the problem.
Edit 1/31: On my Vista Ultimate x64 laptop (an old Dell Inspiron e1405 laptop) I was missing the latest user32.dll fix - KB3205638. Installed that one along with KB4012583, KB4014793, KB4056941 (KB4015380 is superseded/replaced by KB4056941), KB4056944 (KB4015195 is replaced by KB4056944) and for KB4056568 for IE9 [supersedes KB4041661] and a fresh WU scan took about half an hour to show available Vista updates.