Messenger of Allah said: "Whoever sleeps past Al-Witr or forgets it, then let him pray it when he remembers it or when he awakens."  

قَالَ رَسُولُ اللَّهِ ﷺ مَنْ نَامَ عَنِ الْوِتْرِ أَوْ نَسِيَهُ فَلْيُصَلِّ إِذَا ذَكَرَ وَإِذَا اسْتَيْقَظَ  

the Prophet said: "Whoever sleeps past his Al-Witr then let him pray it in the morning."  

أَنَّ النَّبِيَّ ﷺ قَالَ مَنْ نَامَ عَنْ وِتْرِهِ فَلْيُصَلِّ إِذَا أَصْبَحَ