I know that if this does turn out to be a legit security issue, Paypal's engineers will soon deploy a fix, after which I will just re-associate it.
The procedure is:
1) log into your paypal account
2) click "profile"
3) Click on "My Money"; or if you don't see that, look for the subheading "Financial Information" and click "Bank accounts"
4) You should see a link for the bank account; select it
5) click "Remove"
6) *confirm* on the next screen (be sure to click that "confirm remove" button)
7) See the confirmation message
That's it. Depending on your Paypal balance, you may want to try transferring funds into the account before dissociating. [EDIT: Or maybe not, sounds like it could block the disassociation procedure - check the comments below.] I don't know if you can do both in sequence quickly; fortunately our paypal balance happened to be really low today.