My mother took out a credit card in my name and accumulated debt

I'm literally in shock, the bank called me this morning to say my debt is in arrears. It turns out my mom knew my passwords and went and got a card in my name, spent money and bought some things. Now she says she can't pay it back, but my credit score will be ruined, I'm so angry. It's family after all, so I can't say much, but how can there be such irresponsibility? I'm at a loss as to what to do; should I pursue legal action or just let it go? I don't know.