CVE-2021-37713 Arbitrary File Creation/Overwrite on Windows via insufficient relative path sanitization
Arbitrary file creation and code execution via path traversal on Windows in node-tar due to insufficient sanitization of drive-letter paths.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2021-37713?
CVE-2021-37713 is a high-severity path traversal vulnerability in Oracle Graalvm, published on 31 Aug 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
The npm package "tar" (aka node-tar) before versions 4.4.18, 5.0.10, and 6.1.9 has an arbitrary file creation/overwrite and arbitrary code execution vulnerability. node-tar aims to guarantee that any file whose location would be outside of the extraction target directory is not extracted. This is, in part, accomplished by sanitizing absolute paths of entries within the archive, skipping archive entries that contain `..` path portions, and resolving the sanitized paths against the extraction target directory. This logic was insufficient on Windows systems when extracting tar files that contained a path that was not an absolute path, but specified a drive letter different from the extraction target, such as `C:some\path`. If the drive letter does not match the extraction target, for example `D:\extraction\dir`, then the result of `path.resolve(extractionDirectory, entryPath)` would resolve against the current working directory on the `C:` drive, rather than the extraction target directory. Additionally, a `..` portion of the path could occur immediately after the drive letter, such as `C:../foo`, and was not properly sanitized by the logic that checked for `..` within the normalized and split portions of the path. This only affects users of `node-tar` on Windows systems. These issues were addressed in releases 4.4.18, 5.0.10 and 6.1.9. 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. There is no reasonable way to work around this issue without performing the same path normalization procedures that node-tar now does. Users are encouraged to upgrade to the latest patched versions of node-tar, rather than attempt to sanitize paths themselves.
Weakness: CWE-22
Which versions are affected by CVE-2021-37713?
6 open source packages ship an affected version, including tar. It affects 3 products.
| Package | Affected | Fixed in |
|---|---|---|
tar npm | All versions | 4.4.18 |
tar npm | All versions | 4.4.18 |
tar npm | From 5.0.0 | 5.0.10 |
tar npm | From 5.0.0 | 5.0.10 |
tar npm | From 6.0.0 | 6.1.9 |
tar npm | From 6.0.0 | 6.1.9 |
Products include Npmjs Tar, Oracle Graalvm, Siemens Sinec Infrastructure Network Services.
How do I fix CVE-2021-37713?
Upgrade tar to a fixed version for your release line: 4.4.18, 5.0.10 or 6.1.9.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2021-37713 being exploited?
There is no known exploitation of CVE-2021-37713 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2021-37713, CLEANSTART-2026-BE95243, CLEANSTART-2026-BX59752, GHSA-5955-9wpr-37jh, ROOT-APP-NPM-CVE-2021-37713.