You should be able to obtain this update from the Autodesk Desktop App, unless you have chosen to not use this app or your company blocks it, etc. – in which case you will have to go find it using a few more steps.
AutoCAD/AutoCAD LT 2018.0.2 Update
As announced on the official AutoCAD blog, Autodesk introduced a problem with the 2018.0.1 Update, and then resolved the issue by releasing the AutoCAD 2018.0.2/AutoCAD LT 2018.0.2 Update. As this update fixes a defect that would cause the product to not start, it is critical for users who installed the initial 2018.0.1 Update to install the AutoCAD 2018.0.2/AutoCAD LT 2018.0.2 Update as soon as possible and before June 1, 2017.
