recently Apple issued a security patch for Safari that apparently was related to the use of the opensource webkit code. Since this code is also used by QtWebkit isn’t it also affected?
there is a critical advisory using KDE3 and KDE4 outlined at Secunia.com that they claim to be unresolved because of this.
KDE Multiple Vulnerabilities - Secunia Advisories - Vulnerability Information - Secunia.com