Microsoft has announced a “critical vulnerability in its software’s handling of the ubiquitous JPEG graphics format,” reports The Register. According to the report, the security hole gives hackers the ability to create a special JPEG graphics file that when viewed through Internet Explorer, Outlook, Word, or other software, would give the attacker control of the PC. Currently affected systems include Windows XP, Windows Server 2003 and Office XP. At present Macs are not vulnerable to the virus.