policycoreutils is a collection of SELinux policy utilities.
The seunshare utility is owned by root with 4755 permissions which can be exploited by a setuid system call.
A local attacker may be able to gain escalated privileges.
There is no known workaround at this time.
All policycoreutils users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose
">=sys-apps/policycoreutils-2.2.5-r4"