Via HackerOne. When you view a raw file in Differential, we currently generate a permanent file with default permissions. This may be incorrect: default permissions may be broader than the diff's permissions.
The other three methods of downloading/viewing raw files ("Download" in Diffusion and Differential, "View Raw" in Diffusion and Differential) already apply policies correctly and generate temporary files. However, this workflow was missed when other workflows were updated.
Beyond updating the workflow, delete any files we've generated in the past. This wipes the slate clean on any security issues and frees up a little disk space.