Attackers can also use the notepad installer as a payload execution mechanism. To run your malware, just get older notepad++ installers and drop your dll after the installer is running to run it as SYSTEM.

Couple questions as savvy tech person but not working day-to-day in security/IT:

Would a regular home user with an old installer in their Downloads folder need to worry? (is a bad download file going to target looking for these old installers, then moving files around, etc?)

On the other hand, I could see corporate IT having the stronger case of proactively wanting to flag this installer if present on their systems.