gtar -- name mangling symlink vulnerability

Problem Description:
Symlinks created using the “GNUTYPE_NAMES” tar extension can
be absolute due to lack of proper sanity checks.
Impact:
If an attacker can get a user to extract a specially crafted
tar archive the attacker can overwrite arbitrary files with
the permissions of the user running gtar. If file system
permissions allow it, this may allow the attacker to overwrite
important system file (if gtar is being run as root), or
important user configuration files such as .tcshrc or .bashrc,
which would allow the attacker to run arbitrary commands.
Workaround:
Use “bsdtar”, which is the default tar implementation in
FreeBSD 5.3 and higher. For FreeBSD 4.x, bsdtar is available
in the FreeBSD Ports Collection as
ports/archivers/libarchive.