Due to a security flaw that was dubbed critical, Microsoft has released an emergency patch to remedy the issue.

Microsoft said in a security bulletin that the security flaw could give an attacker the opportunity to install programs, view, change, delete data or create new accounts with full user rights. The technology company dubbed the vulnerability as critical and considered it a highest threat, ABC News reported.

Microsoft programs such as Windows Vista, Windows 7, Windows 8, Windows 8.1 and Windows RT could all be affected by the security flaw. The security flaw is triggered when a user opens a damaged document or goes to a website with malicious OpenType fonts which are a type of font file created by Adobe and Microsoft. As many as one billion PCs around the world could be in danger of being damaged by the security flaw. A Microsoft spokesperson said that Windows 10 Insider Preview, is also affected by the flaw.

The vulnerability was discovered by FireEye's security experts, which are part of Google's Project Zero team. Mashable reported that after looking through the leaked documents of an Italian security company from the Hacking Team, the security flaw was found. The flaw was discovered in a 400GB of stolen data, after the operation of the security team. Hacking Team is a company that makes surveillance software for governments.

Adobe earlier has acknowledged that the flaw exists and marked it as a critical vulnerability. The company's security bulletin said that the flaw also affects Adobe Flash Player 18.0.0.194 and earlier versions for Mac and Linux aside from Windows.

According to its internal documents, the flash bug is potent and could cause damage to the computer programs. It described that the flaw could do severe damage by causing a crash and allow a hacker to take control of the damaged system. It was reported that the hackers are already exploiting the security flaw.

Before Microsoft released the security patch, the 32-bit and 64-bit versions of Windows were affected, allowing an attacker to take control of the victim's computer. However, for the vulnerability to be effective, it would have to be used in conjunction with another vulnerability.

An internal document from the Hacking Team detailed that the capabilities of its surveillance software showed that it could be used to monitor Skype, Facebook, Gmail and other communication portals as well as cryptocurrency transactions.

For security measures, all windows users are advised to upgrade their Personal Computers via Windows Update.