CVE-2021-32804

The npm package “tar” (aka node-tar) before versions 6.1.1, 5.0.6, 4.4.14,
and 3.3.2 has a arbitrary File Creation/Overwrite vulnerability due to
insufficient absolute path sanitization. node-tar aims to prevent
extraction of absolute file paths by turning absolute paths into relative
paths when the preservePaths flag is not set to true. This is achieved
by stripping the absolute path root from any absolute file paths contained
in a tar file. For example /home/user/.bashrc would turn into
home/user/.bashrc. This logic was insufficient when file paths contained
repeated path roots such as ////home/user/.bashrc. node-tar would only
strip a single path root from such paths. When given an absolute file path
with repeating path roots, the resulting path (e.g. ///home/user/.bashrc)
would still resolve to an absolute path, thus allowing arbitrary file
creation and overwrite. This issue was addressed in releases 3.2.2, 4.4.14,
5.0.6 and 6.1.1. Users may work around this vulnerability without upgrading
by creating a custom onentry method which sanitizes the entry.path or a
filter method which removes entries with absolute paths. See referenced
GitHub Advisory for details. Be aware of CVE-2021-32803 which fixes a
similar bug in later versions of tar.