Israeli-based software research agency, NorthBit, has released a report that claims millions of Android devices might be vulnerable to hacking, TNW News reports.

According to NorthBit’s research, the security concern comes from Stagefright, Android’s mediaserver and multimedia library.

NorthBit says that devices running Android versions 2.2 through 4.0 as well as 5.0 and 5.1 are most susceptible to the new exploit.

The research additionally estimates that there’s about 275 million devices running the compromised versions, though it is difficult to tell how many of them might be at danger.

NorthBit says that particularly vulnerable to attacks are Nexus 5 devices running stock ROM. Other models that the company has successfully hacked include HTC One, LG G3 and Samsung S5.