Restricted Views backed objects (OSV1) could be bypassed under specific circumstances due to a software bug, this could have allowed users that didn't have permission to see such objects to view them via Object Explorer directly. This software bug did not impact or otherwise make data available across organizational boundaries nor did it allow for data to be viewed or accessed by unauthenticated users.  
The affected service have been patched and automatically deployed to all Apollo-managed Foundry instances.