Samsung's Galaxy S7 smartphones contain a security flaw, uncovered earlier this year, that put tens of millions of devices at risk to hackers.

Researchers from Austria's Graz Technical University told Reuters they have figured out a way to exploit the Meltdown vulnerability to attack Galaxy S7 handsets.

Smartphones made by Samsung were previously thought to be immune to a security vulnerability known as Meltdown, which researchers said affected most of the world's PCs, smartphones and other computing devices.

The team plans to release their findings on Wednesday at the Black Hat security conference in Las Vegas. They are looking into Meltdown's impact on other makes and models of smartphones and expect to uncover more vulnerable devices in the near future, researcher Michael Schwarz told Reuters.

Samsung said it created a patch to protect Galaxy S7 handsets against Meltdown that it began pushing out to affected users last month.

Meltdown, and a second vulnerability known as Spectre, can be exploited to reveal the contents of a computer device's central processing unit. Hackers can exploit those vulnerabilities by either bypassing hardware barriers or tricking applications into giving up secret information such as passwords or banking details.