Is Winterthorn Blessing legal in Standard, Modern, and Commander?

Winterthorn Blessing is legal in: Modern, Pioneer, Legacy, Vintage, Commander, Historic.

Winterthorn Blessing

Q: What type of card is Winterthorn Blessing?

Winterthorn Blessing is a Sorcery. Its oracle text reads: "Put a +1/+1 counter on up to one target creature you control. Tap up to one target creature you don't control, and that creature doesn't untap during its controller's next untap step. Flashback {1}{G}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)"

Sorcery

Put a +1/+1 counter on up to one target creature you control. Tap up to one target creature you don't control, and that creature doesn't untap during its controller's next untap step.

Flashback (You may cast this card from your graveyard for its flashback cost. Then exile it.)