Q: Status of Fasting in Rajab?

Keeping all views in mind…
You will not find direct crisp Sahih Hadith on fasting alone in Rajab or on any specific days of Rajab.
However, it is one of the sacred months and according to scholars, it is mustahabb to fast during the sacred months.
Thus if a person fasts during Rajab because of this, and he also fasts in the other sacred months, there is nothing wrong with that.
But singling out Rajab for fasting is not right.

Question :
Is the following Dua Masnoon and can we recite it if it’s not?

“ O Allah, bless us in Rajab and Sha‘baan, and let us reach Ramadan”.
According to Ibn Ma’een this isnaad(chain) is da‘eef (weak).

But we know that it is better to be regular in Qur’anic and Masnoon du’as but if there is some good dua and there are no problematic words in it then we can obviously read it.

So all such du’as that are not in ahadith or not in Sahih hadith but their wordings are ok then you can recite it.

With regard to the Muslim asking his Lord to let him reach Ramadan, there is nothing wrong with that.

Al-Haafiz Ibn Rajab (may Allah have mercy on him) said:

Ma‘alla ibn al-Fadl said: They used to pray to Allah for six months, may He be exalted, asking Him to cause them to reach Ramadan, and they used to call upon Him for six months asking Him to accept it from them. Yahya ibn Abi Katheer said: One of their duas was: “O Allah, keep me safe until Ramadan, keep Ramadan safe for me, and accept it from me.”

Lataa’if al-Ma‘aarif (p. 148)

May Allah SWT forgive my shortcomings.
Aamen

Aiasha Amir