Is it permissible to apply masah over boots?
Shoes like boots that cover feet with anklebones just like the khuffs are also considered as khuffs. In this respect, a person may apply masah over boots that are worn when he is in the state of ablution, and may establish prayer without taking them off. However, if there is something ritually impure on or under boots which prevents one from establishing prayer, he needs to clean it first. (Marghinani, al-Hidayah, I, 201, 202; Mawsili, al-Ikhtiyar, I, 92, 93)
Source: Presidency Of Religious Affairs The Turkey, High Board of Religious Affairs FATWAS