Chances are they all are. Just that some bugs are not yet public knowledge.
MS have been aware of some activity trying to exploit this, If concerned then use a different browser until the fix is distributed. Personally I get fed up at the number of times IE freezes and needs restarting, anyway. (Especially at this site for some reason.)
I have no problem with IE11 as there are bugs trying to exploit everything on the Internet.
Uninstalled Firefox some time ago as it's overrated, some people seem to think that the sun shines out of it's ****
Nothing is Immune to all the nasties out there, but a good Anti-Virus helps
//There are a few i use recommended to me by a colleague in the security services which i couldn't possibly disclose but they appear to be safe and free from the bugs, viruses and hidden agendas from the the most commonly used ones. //
Well, given that this is a site where a lot of folk come for suggestions to queries ; why didn't you just say what you use ; instead of this nonsense ?
''There are a few i use recommended to me by a colleague in the security services which i couldn't possibly disclose ...''