Facebook today revealed that more nearly 50 million accounts have been affected by a "security issue." Discovered by Facebook's engineering team on September 25, the issue allowed attackers to take over people's accounts by stealing Facebook access tokens.
From Facebook:
Our investigation is still in its early stages. But it's clear that attackers exploited a vulnerability in Facebook's code that impacted "View As", a feature that lets people see what their own profile looks like to someone else. This allowed them to steal Facebook access tokens which they could then use to take over people's accounts. Access tokens are the equivalent of digital keys that keep people logged in to Facebook so they don't need to re-enter their password every time they use the app.
This attack exploited the complex interaction of multiple issues in our code. It stemmed from a change we made to our video uploading feature in July 2017, which impacted "View As." The attackers not only needed to find this vulnerability and use it to get an access token, they then had to pivot from that account to others to steal more tokens.
In response, Facebook has reset the access tokens of the nearly 50 million accounts that it is aware were affected by the breach. Further, the company says it is resetting tokens for an additional 50 million accounts as a precautionary measure.
As a result, people who have had their security tokens reset will have to log back into the Facebook and any of the Facebook apps they were previously logged into.
Given the avenue of attack, Facebook has also opted to turn off the "View As" feature as it conducts a security review. Currently, there's no indication as to who was behind the attack, but Facebook says it has reached out to law enforcement and has fixed the vulnerability.
Facebook, Privacy, and You: The Ultimate Guide

Windows 10 build 19035 rolls out to Fast and Slow ring Insiders
Another new Windows 10 preview build is headed out to Insiders today. Both Slow and Fast ring Insiders can download build 19035, which brings another batch of fixes and improvements, but no new features.

Microsoft 365 for consumers could arrive in Spring 2020
Microsoft might release a subscription called "Microsoft 365 Life" in 2020 according to a new report.

Everything (we think) we know so far about Xbox 'Project Scarlett'
Microsoft might be gearing up not one, but two consoles to tackle next-gen gaming. Here's what we think we know so far about 'Project Scarlett.'

These Black Friday deals let you grab some excellent apps at a discount
Several app developers have jumped on the Black Friday train, letting you saving money on some of the best apps in the Microsoft Store.