Today I read about a flaw that supposedly went unused and unnoticed in the Enterprise version of McAfee:
Mcafee Vulnerability
Interestingly enough this exploit allows control over the machine to steal files and data.
Based on personal experience, other versions of McAfee may have issues as well. I can't pinpoint it, but when I install the software, I have problems.
This is really sad because McAfee has some cool concepts in their firewall software, for instance.