The Tar program provides the ability to create and manipulate tar archives.
Tar does not properly extract archive elements using the GNUTYPE_NAMES record name, allowing files to be created at arbitrary locations using symlinks. Once a symlink is extracted, files after the symlink in the archive will be extracted to the destination of the symlink.
An attacker could entice a user to extract a specially crafted tar archive, possibly allowing for the overwriting of arbitrary files on the system extracting the archive.
There is no known workaround at this time.
All Tar users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=app-arch/tar-1.16-r2"