fence is an I/O group fencing system.
The fence_apc, fence_apc_snmp (CVE-2008-4579) and fence_manual (CVE-2008-4580) programs contain symlink vulnerabilities.
These vulnerabilities may allow arbitrary files to be overwritten with root privileges.
There is no known workaround at this time.
Gentoo discontinued support for fence. All fence users should uninstall and choose another software that provides the same functionality.
# emerge --unmerge sys-cluster/fence