Hadith 216B

قَالَ مَالِك فِيمَنْ سَهَا فِي صَلَاتِهِ فَقَامَ بَعْدَ إِتْمَامِهِ الْأَرْبَعَ ، فَقَرَأَ ثُمَّ رَكَعَ ، فَلَمَّا رَفَعَ رَأْسَهُ مِنْ رُكُوعِهِ ذَكَرَ أَنَّهُ قَدْ كَانَ أَتَمَّ : إِنَّهُ يَرْجِعُ فَيَجْلِسُ وَلَا يَسْجُدُ ، وَلَوْ سَجَدَ إِحْدَى السَّجْدَتَيْنِ لَمْ أَرَ أَنْ يَسْجُدَ الْأُخْرَى ، ثُمَّ إِذَا قَضَى صَلَاتَهُ فَلْيَسْجُدْ سَجْدَتَيْنِ وَهُوَ جَالِسٌ بَعْدَ التَّسْلِيمِ
Imam Malik, may Allah have mercy on him, said: If a person, after completing four rak'ahs, stands up by mistake and recites (Qur'an) and performs ruku', then when he raises his head from ruku' he remembers that he had already completed the four rak'ahs and established the prayer, then that person should sit down and not perform sujud. And if he has already performed one sujud, he should not perform the second. Then he should recite the tashahhud and perform two sujud of forgetfulness after the salam.
Hadith Reference موطا امام مالك رواية يحييٰ / كتاب الصلاة / 216B
Hadith Takhrij «شركة الحروف نمبر: 205، فواد عبدالباقي نمبر: 3 - كِتَابُ الصَّلَاةِ-ح: 66»