A month and a half is plenty of time, but it requires (1) the company decides that fixing security bugs is top priority. (2) They need a senior engineer or two on hand who are smart enough to understand the issues involved and implement a fix. And (3) They need a decent release process which allows security fixes to be promptly rolled out to users.
I’m not sure where most companies fail here. It’s certainly easy to downplay and deprioritize security fixes from the inside, when you have a big deadline coming up, or your customers are yelling at you or a refactor is blocking other people from doing their job. Security issues from the inside never feel like the “all hands on deck” emergency situations that security researchers believe them to be. (And I’m not sure if this is right or wrong, just, the experience I’ve always had from the ground when security issues potentially affected us.)