Google Play apps bombard users with 'horrible, intrusive' ads and deplete their battery
Bitdefender says apps affected include a racing simulator, several QR code scanners and a weather app.
New version of operating system comes with wide array of bug fixes.
Apple has released its later iPhone and iPad operating system, and users have been urged to download it.
The update marks the first time the latest software has been available for the iPad, and includes a range of vital updates for iPhones.
Those phones that downloaded last week's iOS 13 update but have not yet upgraded to iOS 13.1 are vulnerable to a whole host of bugs, which arrived with the latest software.
The majority of the changes are bug fixes, and the list of those is vast. The notes on the update make mention of bug fixes in Mail, Messages, Reminders, Notes, the camera, the home screen and more – and there may be other changes that are not listed.
Updating an iPhone is simple: head to the Settings app, click "general" and choose the software update option. iOS also now tries to update itself automatically, meaning that phones could already have fixed themselves while they are plugged in overnight.