Does the taste of blood in the throat, resulting from a nosebleed or cracked lips, invalidate the fast?

If the blood does not reach the stomach or the throat, then there is no issue. If it reaches them unintentionally, the fast is valid according to the Shafi'is and Hanbalis. As for the Hanafis and Malikis, they hold that if a person has a nosebleed and the blood comes out of their mouth without returning to their throat, then there is nothing against them. However, if the blood from the nosebleed enters their throat, their fast is broken.