The past few days, there were some accounts being easily accessed on Steam which had the true owners losing their account for a bit. The security flaw consisted of asking to do a password reset and then just submitting a blank verification code in Steam.
Once done, it would just take you the password change screen. There seemed to be no validation on the recovery code entry to make sure that blank doesn't bypass it and take you to the password reset screen.
The good news is that it's been fixed. Valve learned of it on July 25th and fixed it the next day. Do you have to reset your own password? No, it never revealed any login or financial information so you should be good to go.
Below is the video of it in action, but you can't do it anymore so don't try and go steal other people's Steam accounts.