CVE-2018-20990
Links in archives can overwrite any existing file
Description
When unpacking a tarball with the `unpack_in`-family of functions it's intended that only files within the specified directory are able to be written. Tarballs with hard links or symlinks, however, can be used to overwrite any file on the filesystem. Tarballs can contain multiple entries for the same file. A tarball which first contains an entry for a hard link or symlink pointing to any file on the filesystem will have the link created, and then afterwards if the same file is listed in the tarball the hard link will be rewritten and any file can be rewritten on the filesystem. This has been fixed in https://github.com/alexcrichton/tar-rs/pull/156 and is published as `tar` 0.4.16. Thanks to Max Justicz for discovering this and emailing about the issue!
How to fix CVE-2018-20990
To remediate CVE-2018-20990, upgrade the affected package to a fixed version below.
- —upgrade to 0.4.16 or later
- —upgrade to 0.4.16 or later
Is CVE-2018-20990 being exploited?
Low — EPSS is 0.3%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0, < 0.4.16
- >= 0.0.0-0, < 0.4.16
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.5 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |