Hackers have found a way to make hotel master keys out of a commonly used key card. Consultants for Finnish data security company F-Secure say they discovered the vulnerability about a year ago and reported it to Assa Abloy, a lock manufacturer who owns the security system that has been hacked.

Assa Abloy says security measures have been implemented by some hotels through a software update, but it will most likely take several weeks to completely resolve the issue. According to Assa Abloy, there are still several hundred thousand hotel rooms around the world using the room security system still vulnerable to a hacked master key.