When importing "Participant" records for CiviEvent, some inputs were not suitably escaped.
All versions less than or equal to: 5.47.1, 5.46.2, 5.45.3
CiviCRM version 5.46.3. 5.47.2, 5.45.4 ESR
If you are not on the ESR and haven't yet upgraded to 5.47 upgrade to 5.46.3, if you have upgraded to 5.47 then upgrade to 5.47.2
Mathieu Lutfy of Coop SymbioTIC for reporting the issue and fixing the issue