I say, and with God's success: If the shoe is made of cotton or similar material and is worn alone, it is not permissible to wipe over it; because it is not possible to walk on it. Likewise, if it is worn over the shoes, it is not permissible to wipe over it unless it is such that water does not penetrate to the inner shoe, then it is permissible to wipe over it; as the intended purpose is achieved. Refer to: Sharh Al-Wiqayah p. 114, and Nihayat Al-Murad p. 387, and God knows best.