Software developer Adobe is working on a patch for a "critical" vulnerability that is present in the company's PDF software. The bug, present in both Reader and Acrobat, will allow hackers to gain full access of a computer and is currently being exploited. You should avoid opening PDFs unless you know the sender and trust them.

The bug is present in Adobe Reader XI, 11.0.01 and earlier; Reader X, 10.1.5 and earlier; Reader 9.5.3 and earlier. Acrobat versions similarly numbered are also vulnerable. The bug is present across all platforms including Mac, PC, and Linux.

Adobe has suggested users make use of the 'Protected View" option given by the software if they have to open a PDF. An estimated time of arrival has not been given for the patch.