It's an error in the score. The Dx on the & of beat 2 should be a Cx.
The below image comes from the Breitkopf and Härtel first edition on IMSLP. Other scores there corroborate. The Busoni edition ("Franz Liszt: Complete Etudes for Solo Piano, Series II" [1988, Dover]) also agrees.
EDIT: As pointed out in the comments (@James Martin), the lower E on beat 5 should be a D#.