fileio.c in Vim prior to 8.0.1263 sets the group ownership of a .swp file to the editor's primary group (which may be different from the group ownership of the original file), which allows local users to obtain sensitive information by leveraging an applicable group membership, as demonstrated by /etc/shadow owned by root:shadow mode 0640, but /etc/.shadow.swp owned by root:users mode 0640, a different vulnerability than CVE-2017-1000382.
Created vim tracking bugs for this issue:
Affects: fedora-26 [bug 1524489]
In Red Hat Enterprise Linux, the default primary group is unique to the user (e.g.: root's primary group is root, user1's primary group will be user1, etc.).
Thus unless default primary group is modified at creation time, or at execution time (e.g. via newgrp or sg), this vulnerability will not be effective.
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/.