CVE-2021-32803

The npm package “tar” (aka node-tar) before versions 6.1.2, 5.0.7, 4.4.15,
and 3.2.3 has an arbitrary File Creation/Overwrite vulnerability via
insufficient symlink protection. node-tar aims to guarantee that any file
whose location would be modified by a symbolic link is not extracted. This
is, in part, achieved by ensuring that extracted directories are not
symlinks. Additionally, in order to prevent unnecessary stat calls to
determine whether a given path is a directory, paths are cached when
directories are created. This logic was insufficient when extracting tar
files that contained both a directory and a symlink with the same name as
the directory. This order of operations resulted in the directory being
created and added to the node-tar directory cache. When a directory is
present in the directory cache, subsequent calls to mkdir for that
directory are skipped. However, this is also where node-tar checks for
symlinks occur. By first creating a directory, and then replacing that
directory with a symlink, it was thus possible to bypass node-tar symlink
checks on directories, essentially allowing an untrusted tar file to
symlink into an arbitrary location and subsequently extracting arbitrary
files into that location, thus allowing arbitrary file creation and
overwrite. This issue was addressed in releases 3.2.3, 4.4.15, 5.0.7 and
6.1.2.