A new Web site allows Apple customers to jailbreak their devices merely by visiting the site with their iPhone, iPad or iTouch. Researchers soon learned that the site leverages two previously unknown security vulnerabilities in the PDF reader functionality built into Apples iOS4. Apple says it plans to release an update to quash the bugs. Interestingly, this same attack does appear to affect Foxit Reader, a free PDF reader that I often recommend as an alternative to Adobe Reader. Im left wondering what to call these sorts of vulnerabilities that quite obviously give users the freedom that jailbreaking their device(s) allows.”]
Source: https://krebsonsecurity.com/2010/08/foxit-fix-for-jailbreak-pdf-flaw/