Whoever performed the Zuhr with five Rak’ah because he forgot
حَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ، وَأَبُو بَكْرِ بْنُ خَلاَّدٍ قَالاَ حَدَّثَنَا يَحْيَى بْنُ سَعِيدٍ، عَنْ شُعْبَةَ، حَدَّثَنِي الْحَكَمُ، عَنْ إِبْرَاهِيمَ، عَنْ عَلْقَمَةَ، عَنْ عَبْدِ اللَّهِ، قَالَ: صَلَّى النَّبِيُّ ـ صلى الله عليه وسلم ـ الظُّهْرَ خَمْسًا. فَقِيلَ لَهُ: أَزِيدَ فِي الصَّلاَةِ؟ قَالَ " وَمَا ذَاكَ؟ " . فَقِيلَ لَهُ . فَثَنَى رِجْلَهُ، فَسَجَدَ سَجْدَتَيْنِ .
It was narrated that ‘Abdullah said: “(Once) the Prophet (ﷺ) prayed Zuhr with five Rak’ah, and it was said to him: ‘Has something been added to the prayer?’ He said: ‘What is that?’ They told him, and he turned back towards the Qiblah and performed two prostrations.”