With so many models, Android manufacturers are more likely focused on newer, shinier phones than older ones, so security lapses can remain unresolved.
More than half of all Android devices don't have security patches and are vulnerable to malware, according to a security company.
The findings are based on data from Duo Security, who not coincidentally also produced the free X-Ray for Android app, according to InformationWeek.
"The stat is based on over 20,000 users who downloaded and ran the X-Ray mobile application on their device, and the current global distribution of Android versions," Jon Oberheide, CTO of Duo Security, told Information Week via email.
Oberheide said he knew the statistic would be hard for Android users to hear, but the lack of security patches is appalling. "Yes, it's a scary number, but it exemplifies how important expedient patching is to mobile security and how poorly the industry--carriers, device manufacturers, etc.--has performed thus far," Oberheide wrote on the Duo Security blog.