In theory they can, but it's very unlikely, as it requires a 2/3rds majority in both the Assembly and the Senate. One of the things I severely dislike about California politics is that the Governor's veto power is near absolute in practice. On top of that this state has an entrenched political machine that has invested in Newsom since he ran for Mayor of San Francisco - and many in Sacramento owe their careers to him. There's no realistic chance any of these vetoes get overridden.