The update fixes two important security flaws, one of which was just recently publicized and three relatively minor bugs in macOS High Sierra.
This has already reported it to Apple, so we can expect a fix in the next update or so. Still, it’s weird that a vulnerability like this slipped through the cracks.
Remember the big Yahoo! data breach where a billion user accounts where compromised? Turns out it was really 3 billion, or every single Yahoo! account.
A new Mac security threat called keychainStealer could expose your Keychain passwords, but it isn’t limited to High Sierra, and isn’t a reason to not upgrade.
Most people probably won’t see this dialog box though. It will only appear if your Mac thinks something fishy is going on.
Apple, as companies get hacked left and right, it’s time to reassure users as well as security experts that you really do have our backs.