Minor Update for Chrome OS Released for Most Devices
A small security and bug fix update is currently rolling out for most devices in the Chrome OS Stable channel. The update takes devices to build 58.0.3029.112 (Platform version: 9334.69.0). This build from the Chromium team appears to be for a wide range of devices with no exceptions noted in the release notes. This is somewhat different than the last few major releases as there have been specific devices excluded from the updates. Those devices have been for the most part the handful of Chromebooks and Chromeboxes that can run Android apps.
As for what is fixed in this update or patched, that information was not released. That is the SOP (Standard Operating Procedure) for the Chrome OS team as they tend to not release specifics on an update until the majority of devices have been updated.