Four major security holes in the Qualcomm chips which power modern Android devices have left as many as 900 million users vulnerable to a range of attacks.

According to Israel-based security firm Checkpoint, the flaws—dubbed "Quadrooter"—found in the firmware which governs the chips, could allow potential attackers to "trigger privilege escalations for the purpose of gaining root access to a device" using malware which wouldn't require special permissions, allowing it to pass under suspicious users' radars.

Qualcomm makes chips for the majority of the world's phones, holding a 65 percent share of the market. Most of the major recent Android devices are expected to be affected by the flaw, including:

BlackBerry Priv

Blackphone 1 and Blackphone 2

Google Nexus 5X, Nexus 6, and Nexus 6P

HTC One, HTC M9, and HTC 10

LG G4, LG G5, and LG V10

New Moto X by Motorola

OnePlus One, OnePlus 2, and OnePlus 3

Samsung Galaxy S7 and Samsung S7 Edge

Sony Xperia Z Ultra

Three of the four holes have already been patched, with a solution for the fourth on the way. However, most users are at the mercy of their handset manufacturers if they want these patches applied. Owners of Google's Nexus devices have already had patches pushed to their phones, but other manufacturers have historically been less interested in patching flaws found in their devices after release.

According to Checkpoint—which revealed its findings over the weekend at the Defcon security conference in Las Vegas—the "vulnerabilities can give attackers complete control of devices and unrestricted access to sensitive personal and enterprise data on them."

Since the vulnerable drivers are pre-installed on devices at the point of manufacture, they can only be fixed by installing a patch from the distributor or carrier. Distributors and carriers issuing patches can only do so after receiving fixed driver packs from Qualcomm. This situation highlights the inherent risks in the Android security model. Critical security updates must pass through the entire supply chain before they can be made available to end users. Once available, the end users must then be sure to install these updates to protect their devices and data.

In a statement, a Qualcomm spokesperson said: