Arbitrary File Write Affecting tar package, versions >=6.0.0 <6.1.9 >=5.0.0 <5.0.10 <4.4.18

  • Attack Complexity


  • User Interaction


  • Scope


  • Confidentiality


  • Integrity


Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • snyk-id


  • published

    1 Sep 2021

  • disclosed

    1 Sep 2021

  • credit

    ginkoid, chen-robert, JarLob

How to fix?

Upgrade tar to version 6.1.9, 5.0.10, 4.4.18 or higher.


tar is a full-featured Tar for Node.js.

Affected versions of this package are vulnerable to Arbitrary File Write. 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 is insufficient when extracting tar files that contain two directories and a symlink with names containing unicode values that normalized to the same value. Additionally, on Windows systems, long path portions would resolve to the same file system entities as their 8.3 "short path" counterparts. A specially crafted tar archive can include directories with two forms of the path that resolve to the same file system entity, followed by a symbolic link with a name in the first form, lastly followed by a file using the second form. This leads to bypassing node-tar symlink checks on directories, essentially allowing an untrusted tar file to symlink into an arbitrary location and extracting arbitrary files into that location.