Abdullah bin Masud reported,

The Messenger of Allah ﷺ prayed Dhuhr as five rakahs. He was asked, "Has the prayer been increased?"He replied, "What do you mean?"They said, "You prayed five rakahs."So he performed two prostrations after he had given the salam.

Azami 2478

Sahih

عن عبد الله بن مسعود

أن رسول الله ﷺ صلى الظهر خمسا، فقيل له: أزيد في الصلاة؟ فقال: ما ذاك؟ قال: صليت خمسا. فسجد سجدتين بعد ما سلم.

الأعظمي 2478صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Prayer
Chapter
Forgetfulness
Section
Prostration of forgetfulness after the taslim
Numbering
Jami al-Kamil 2478 (2nd edition)
Azami 2478