I'm not much for forums or posts, kinda an old guy that only uses net as a resource. I keep getting emails with inserted links from an inactive Yahoo mail account of an old friend. I verified that my friend did not send these messages. It's been hacked or hijacked or whatever and I thought someone at your service would want to know before I delete the acct. from my friends list. I've heard that hacker types love the challenge of busting each other so i copied the link info. Don't have any idea what it all means but i bet one of you smart guys does. Peace.
But basically, change your password as soon as you can. Alternatively, you can go to https://edit.yahoo.com/forgot to re-secure your account. And if you use the same password at any other sites, I recommend you change those as well.