Many traders have complained that their unusuals/high tier items dissapeared from their inventories
This is because there is a malware on Steam right now that steals your items if you visit any Steam Profile and/or your Activity Feed
People are recommended to not visit profiles and their own activity feeds until the issue is solved
And to also run their anti virus for malware inspection
If you think you can be affected, change your Steam password, and enable Mobile Authenticator if you don't have it
No news about whether the items shall be regiven to the affected players
Fortunately I haven't been affected yet, so my unusuals remainWeed, Today 15:56
This was the message I've sent to several trading groups I'm in.
If you have any items of CS:GO, TF2, or anything Valve related, I highly suggets you defend yourself. Change your Steam password, run an anti virus, do what you must.
More info here: https://www.reddit.com/r/Steam/comments/5skfg4/warning_regarding_a_steam_profile_related_exploit/