According to Official Guinness Records,
The highest launch from a Galilean cannon is 11.5 m (37 ft 8 in), and was achieved by Scott Buhr and his AP Physics class (both USA) in Simpsonville, South Carolina, USA, on 2 June 2018. Mr. Buhr and his class were inspired to break the record after watching a video of the previous record achieved by Brian Greene on the "Late Show with Stephen Colbert" in 2016.
For a complete list of 2018 records, please visit 2018 Guinness Records in United States.