Edit:
There has been a newer release of Cordova Android that also fixes some problems with SDK tools 26.x.x
cordova platform update android@6.2.2
or
cordova platform rm android
cordova platform add android@6.2.2
Old answer
Google broke Cordova Android 6.1.x and some other frameworks with their latest sdk tools update.
Cordova Android 6.2.1 has been released and it’s now compatible with latest Android SDK.
You can update your current incompatible android platform with cordova platform update android@6.2.1
Or you can remove the existing platform and add the new one (will delete any manual change you did inside yourProject/platforms/android/ folder)
cordova platform rm android
cordova platform add android@6.2.1
You have to specify the version because current CLI installs 6.1.x by default.