CVE-2021-32803

NameCVE-2021-32803
DescriptionThe 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.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
NVD severitymedium
Debian Bugs992110

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
node-tar (PTS)stretch2.2.1-1fixed
buster4.4.6+ds1-3vulnerable
bullseye6.0.5+ds1+~cs11.3.9-1vulnerable
bookworm, sid6.1.11+~cs11.3.10-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
node-tarsourcestretch(not affected)
node-tarsource(unstable)6.1.7+~cs11.3.10-1992110

Notes

[bullseye] - node-tar <no-dsa> (Minor issue)
[buster] - node-tar <no-dsa> (Minor issue)
[stretch] - node-tar <not-affected> (Vulnerable code introduced later)
https://github.com/npm/node-tar/security/advisories/GHSA-r628-mhmh-qjhw
https://github.com/npm/node-tar/commit/9dbdeb6df8e9dbd96fa9e84341b9d74734be6c20

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