Your bitcoin wallet can get hacked if you aren't careful but the technology itself the blockchain & the whole network can't get hacked.
Someone started this
Threats to bitcoin discussion, check that out if you are more interested in such.
This pretty much sums it up.
I would also warn everyone to check for malicious browser plug ins, some even slip into the Firefox and Chrome repo's, they can detect and change when you copy a wallet address, so always check if you're pasting the correct address.
And phishing is also pretty common through fake emails from exchanges for example, always check the URL.