CVE-2021-37701

The npm package “tar” (aka node-tar) before versions 4.4.16, 5.0.8, and
6.1.7 has an arbitrary file creation/overwrite and arbitrary code execution
vulnerability. 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, where the symlink and directory names in the archive entry used
backslashes as a path separator on posix systems. The cache checking logic
used both \ and / characters as path separators, however \ is a valid
filename character on posix systems. 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. Additionally, a similar confusion could arise on
case-insensitive filesystems. If a tar archive contained a directory at
FOO, followed by a symbolic link named foo, then on case-insensitive
file systems, the creation of the symbolic link would remove the directory
from the filesystem, but not from the internal directory cache, as it
would not be treated as a cache hit. A subsequent file entry within the
FOO directory would then be placed in the target of the symbolic link,
thinking that the directory had already been created. These issues were
addressed in releases 4.4.16, 5.0.8 and 6.1.7. The v3 branch of node-tar
has been deprecated and did not receive patches for these issues. If you
are still using a v3 release we recommend you update to a more recent
version of node-tar. If this is not possible, a workaround is available in
the referenced GHSA-9r2w-394v-53qc.