Actually, it can be hacked since it is a platform but the probability is low.... because the security system is extremely high... but the best way to safe guide yourself is to keep your private key in a secure place never for once share it with people.

for me anything on the net can be hacked, but probably hackers will look for a simplest target than myetherwallet. May be, your computer...
So, before to worry about MEW,if you don't have computer i think you can open it in another device like handphone or something. all you need just private key, don't lose it. your private key is the only way can see your funds.

Hacking of two DNS-servers occurred on April 24 in order to redirect users to a phishing site. As the MEW statement stresses, such an attack technique has been around for about ten years already, and any organization, including large banks, can suffer from it. So MEW can be hacked in such way. Avoiding phishing site and keeping key safe - can help users defense from hackers.