Late last week, the November 2019 security patch was released for the unlocked Galaxy S8 and Galaxy S8+ in the US. Today, T-Mobile is rolling out the latest security update to the Galaxy S8 and S8+ on its network, becoming the first carrier to do so. The November security update for the Galaxy S8/S8+ comes a little over a week after T-Mobile's previous update for the device, which brought improvements to RCS messaging.
The November update for Galaxy devices brings fixes for two critical vulnerabilities. One of those allows unauthorized access to a phone's photos and videos and its camera to malicious apps, while the other allows full control of a device by taking advantage of an exploit within the Chrome web browser. Both vulnerabilities affect Android devices from other manufacturers as well and are not exclusive to Samsung phones and tablets.
T-Mobile's November update for the Galaxy S8 and S8+ is currently available via our firmware database (S8 | S8+). It doesn't seem to have been released over the air yet, but that should change within a day or so. You can check your phone to see if it's already available over the air by opening the Settings app and going into the Software update menu. The software version for the update is G950USQS7DSK2 and G950USQS7DSK2 for the Galaxy S8 and S8+ respectively.