It has been suggested that the security flaw means that personal information is being exposed.
The firm confirmed it is looking into the claims "as quickly as possible".
"HTC takes our customers' security very seriously, and we are working to investigate this claim as quickly as possible," the company said in a statement.
"We will provide an update as soon as we're able to determine the accuracy of the claim and what steps, if any, need to be taken."
It has been revealed that alleged security flaw reveals several key pieces of information, including phone numbers from recent call logs.
Meanwhile, a trade watchdog in the US confirmed recently that it is to investigate claims made by HTC that rival manufacturer Apple is guilty of infringing on its patents.
