The Prophet (ﷺ) said: If anyone oversleeps and misses the witr, or forgets it, he should pray when he remembers.
Sunan Abi Dawud Book 8, Hadith 16
← Previous Hadith When the Messenger of Allah (ﷺ) offered salutation in the witr prayer, he said: Glorify be to the king most holy.

Sunan Abi Dawud Book 8, Hadith 15 Next Hadith → My friend (i.e. the Prophet) instructed me to observe three practices that I do not leave while traveling nor while resident, to pray two rak`ahs in the forenoon, to fast three days every month and not to sleep but after observing the witr.

Sunan Abi Dawud Book 8, Hadith 17