VIM version 8.0.1187 (and other versions most likely) ignores umask when creating a swap file ("[ORIGINAL_FILENAME].swp") resulting in files that may be world readable or otherwise accessible in ways not intended by the user running the vi binary.
Created vim tracking bugs for this issue:
Affects: fedora-all [bug 1508787]
Red Hat Product Security has rated this issue as having Low security impact. This issue is not currently planned to be addressed in future updates. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.