Google announced this month's security patch earlier this week, and after a few other manufacturers announced their own rollouts of the update, now BlackBerry has started rolling it out to their own devices. BlackBerry is usually pretty quick in getting these security updates out - after all, it sells its devices based on the fact that these devices are secure, so rolling out monthly security patches are a pretty big deal. Some months, BlackBerry will beat Google to the punch with these updates, but that wasn't the case in September.
There are quite a few vulnerabilities fixed in this update, most of which were found in AOSP and are ones that Google patched. Since BlackBerry does run mostly stock Android, with a few changes to make it more secure, it would make sense that the majority of the vulnerabilities are actually in AOSP and not in BlackBerry's own software. The company has a vague read out of all of the vulnerabilities patched here on its website. Now, BlackBerry is vague with what was patched because not everyone has the update yet and hasn't applied it yet. So BlackBerry doesn't want to give hackers an easy way to compromise devices. And this is true with all manufacturers, even Google. Most of them will not heavily detail what was changed with these vulnerabilities, to keep hackers in the dark.
BlackBerry is rolling out these updates to the unlocked models sold from Shop BlackBerry first. And that will be followed by the carrier variants. This is because the carrier variants actually need to go through some extra certification before the updates can be rolled out, and thus are slightly delayed. This is always the case, so there's nothing new here really. Those with the BlackBerry KEYone should see the update now. You can head over to Settings, tap on About Phone, then System Updates and Check For Updates. You should be able to download the update from there. It's a somewhat small, but still very important update to download onto your BlackBerry device. So make sure it does get installed and not postponed until later on.