Sunan an-Nasa'i 2350
سنن النسائي#2350SahihAishah said:"The month which the Messenger of Allah most liked to fast was Shaban; indeed he used to join it to Ramadan
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiIsnaad Sahih
In-book reference: 22:261