A very easy way for people to gain access to your Steam account has been fixed after multiple Twitch streamers found that they were locked out of their account. As reported by ryugarulz over on Reddit, streamers Summit1G, Phant0ml0rd, Goldglove and JoshOG, NeoGAF user Lucifon, and YouTuber Elm Hoe (who created the video below). Thankfully the simple hack has now been fixed.
As shown below, someone only needs to know your Steam account name to accomplish this. They go into the logon page for Steam, get to the option that you have forgotten your Steam password, click the option to send a code to your email, then instead of entering in anything just click continue and you can access the account and change the password without ever having to type in a code.