Impact: An application may be able to execute arbitrary code with kernel privileges. Apple is aware of a report that this issue may have been actively exploited. Description: A memory corruption issue was addressed with improved memory handling. There are two clues in there that suggest the fix was for an exploit used by NSO for a zero-click attack, which has been used against iPhones owned by dissidents, activists, human rights lawyers, and opposition politicians.
Link: Speculation that yesterday’s iOS security fix was for NSO exploit