Unpatched, vulnerable PDF readers are a big security issue for private PC users, according to Secunia. 14% of PC users in the US (up from 12.9% last quarter) have an unpatched operating system, and that Oracle Java yet again tops the list of applications exposing PCs to security risks.

The security of a PC is significantly affected by the number and type of applications installed on it, and the extent to which these programs are patched:

• Adobe Reader 10 and 11 come in at number three and four on the Most Exposed List. Adobe Reader 10 with a 25% market share, 39 vulnerabilities and unpatched on 65% of PCs. Adobe Reader 11 with a 55% market share, 40 vulnerabilities and unpatched on 18% of PCs.
• Oracle’s Java JRE 7 tops the list as the most exposed application on the US PCs. With a market share of 54%, 77% of users have not installed the latest updates, despite 101 reported vulnerabilities.
• 1 in 20 programs on the average US PC have reached end-of-life, meaning they are no longer supported by the vendor and do not receive security updates. Adobe Flash Player, one of the end-of-life applications, is still installed on no less than 78% of the PCs.
• Other applications in the top 10 include Apple QuickTime, Microsoft Internet Explorer and uTorrent for Windows.

Source: Unpatched, vulnerable PDF readers leave users open to attack