Google doesn't seem to be paying enough attention on the issue which concerns security.

Heavy security checks are required of them as similar to the checks done for play store versions of the applications.

According to an independent study led by a group in Spain, personal information could be harvested by these pre-installed applications.

A well-known institute of Madrid IMDEA Institute and Stony Brook University checked out the pre-installed apps on the android devices from over 2700 users, over 1700 devices from around 200 vendors all across 130 countries.

The study didn't go deeper about the EU's General Data Protection Regulation laws and the difference they would make.

Android is a highly customized operating system despite its being owned by Google. This includes the packaging of other applications with the operating system before they are delivered to other users.

As per the aforementioned study, a potential threat to users' privacy prevails by the hands of  the infamous pre-installed apps which never undergo the security checks that the other downloaded apps do.

As usually is the case, pre-installed applications could never be uninstalled and aren't even subject to the severe security checks which are a must to keep the users safe.

It was implied by the co-author of the study that apparently no one keeps track of what the pre-installed applications do. There is a major lack of transparency and regulation.

In reply to all of this, Google said that it provides tools to equipment manufacturers which ensures that Google's  privacy and security standards aren't hampered. 

One of Google's spokespersons also mentioned that clear policies regarding the pre-installed applications are given to their partners also that information related with potential hazards is regularly disseminated to them.

The issue of the pre-installed apps has caught fire quite heavily now. A US department of Justice dug into Facebook. Partnerships are also being looked into.