kernelbase.dll
This file is not a system component: windows itself, not a download. Restore it from the source that installed it rather than downloading a replacement.
If the file is already there and Windows still complains, read the message again: “entry point not found” is a different problem from a missing file, and installing the runtime again will not solve it.
Do not download this DLL on its own
Searching for a missing DLL by name leads to sites that hand you that single file. It is one of the oldest and most effective malware delivery methods there is, and a system DLL from an unknown source is indistinguishable from a deliberately modified one. There is never a legitimate reason to obtain a runtime component that way.
The same goes for the tools that offer to do it for you: what a DLL repair tool can and cannot actually fix.
What it is
A core Windows library that has been present since Windows 7 and holds a large part of the low-level API that kernel32 used to implement directly. It is a protected system file and nobody distributes it separately.
Where you see it: Event Viewer and crash dialogs, listed as the "faulting module" when some other program stops working. It shows up far more often as a symptom than as a genuinely missing file.
The important part is what "faulting module: kernelbase.dll" means, because it reads like an accusation and almost never is one. KERNELBASE is where an exception surfaces, not where the bug lives: the code that failed asked Windows to do something, Windows raised the error there, and the crash reporter recorded the last place it passed through. Replacing the file fixes nothing and a copy from a download site can break the machine outright. Read the rest of the Event Viewer entry instead, because the faulting APPLICATION name on the same line is the program that actually needs attention. If kernelbase really is damaged, that is system damage: run "sfc /scannow" and then "DISM /Online /Cleanup-Image /RestoreHealth" from an elevated terminal.
Why there is nothing to download here
There is no verified download we can offer for this one, because installing a file is not the fix. The steps above are what actually resolves it. That distinction matters: the sites ranking for this file name are selling a download that would not have helped even if it were safe.