Growing up in Kelantan and frequenting the suraus, I’m used to reading Surah Yasin three times on the night of the 15th of Shaaban annually. Back then I didn’t hear any objections to the practice.
Nowadays we can hear all sorts of comments such as those made by Shaykh Bin Baz, Dr Yusuf Al Qaradawi and the likes of them. Well, they have every right to say what they know but I beg to differ.
According to Shaykh Abdul Qadir al-Mandili, the dua of Nisfu Shaaban was narrated by Imam Ibnu Abi Shaybah in his Al Musannaf and Imam Ibnu Abi al-Dunya in his Al-Du’a, from the great Sahabi Sayyidina Abdullah Ibnu Mas’ud.
You can read the dua at this blog. I have also copied-pasted it below:
If you can read in arabic you can read the fatwa of Shaykh Atiyyah Saqar concerning Nisfu Shaaban here.