On wikipedia there is a reference to Polaroid 612 which is ISO 20000. Was there faster film? Was there faster film made for specialized purposes (say military, astronomy etc)?
Other than Polaroid 612, no photographic film has been commercially produced at a higher speed than ISO 3200/36°. Konica 3200, Polaroid type 667, and Fujifilm FP-3000B were all rated at ISO 3200/36°.
The normal practice for astronomical work during the film era was to build a mount capable of tracking the sky (in actuality counteracting the Earth's rotation) smoothly enough to allow long exposures of dim objects.
As for whether the military of one of any number of technologically advanced countries ever had faster film, someone might could tell you, but then they might have to kill you!