# CVE-2021-32803: Arbitrary File Creation/Overwrite via insufficient symlink protection due to directory cache poisoning

> Attackers can bypass symlink protections in node-tar to create or overwrite arbitrary files, potentially leading to code execution.

- **Severity:** High 8.2 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N`)
- **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:** Yes
- **Published:** 3 Aug 2021
- **Updated:** 3 Aug 2024
- **Also known as:** CLSA-2026-1775176089, CLSA-2026-1792164455, DEBIAN-CVE-2021-32803, GHSA-r628-mhmh-qjhw, ROOT-APP-NPM-CVE-2021-32803, UBUNTU-CVE-2021-32803, USN-5283-1

## What is CVE-2021-32803?

CVE-2021-32803 is a high-severity path traversal vulnerability in Oracle Graalvm, published on 3 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 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.

Weakness: CWE-59 (Improper Link Resolution Before File Access), CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2021-32803?

8 open source packages ship an affected version, including tar. It affects 3 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `tar` | npm | From 3.0.0 | 3.2.3 |
| `tar` | npm | From 3.0.0 | 3.2.3 |
| `tar` | npm | From 4.0.0 | 4.4.15 |
| `tar` | npm | From 4.0.0 | 4.4.15 |
| `tar` | npm | From 5.0.0 | 5.0.7 |
| `tar` | npm | From 5.0.0 | 5.0.7 |
| `tar` | npm | From 6.0.0 | 6.1.2 |
| `tar` | npm | From 6.0.0 | 6.1.2 |

Products: Oracle Graalvm, Siemens Sinec Infrastructure Network Services, Tar Project Tar.

## How do I fix CVE-2021-32803?

Upgrade tar to a fixed version for your release line: 3.2.3, 4.4.15, 5.0.7 or 6.1.2.

## Is CVE-2021-32803 being exploited?

There is no known exploitation of CVE-2021-32803 in the wild and no public exploit code.

## Other vulnerabilities in Oracle Graalvm

- [CVE-2025-50059](https://insights.sbomify.com/CVE-2025-50059/): Security feature bypass in Oracle GraalVM Enterprise Edition (high 8.6)
- [CVE-2021-32804](https://insights.sbomify.com/CVE-2021-32804/): Arbitrary File Creation/Overwrite due to insufficient absolute path sanitization (high 8.2)
- [CVE-2025-30749](https://insights.sbomify.com/CVE-2025-30749/): Code injection in Oracle GraalVM Enterprise Edition (high 8.1)
- [CVE-2025-50106](https://insights.sbomify.com/CVE-2025-50106/): Code injection in Oracle GraalVM Enterprise Edition (high 8.1)
- [CVE-2026-62574](https://insights.sbomify.com/CVE-2026-62574/): Privilege escalation in Oracle GraalVM Enterprise Edition (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-32803 and fix it if it is affected.

What it is: CVE-2021-32803 is a high-severity path traversal vulnerability in Oracle Graalvm, published on 3 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.
Exploitation: There is no known exploitation of CVE-2021-32803 in the wild and no public exploit code.

Affected packages and fixed versions:
- tar (npm): affected from 3.0.0; fixed in 3.2.3
- tar (npm): affected from 3.0.0; fixed in 3.2.3
- tar (npm): affected from 4.0.0; fixed in 4.4.15
- tar (npm): affected from 4.0.0; fixed in 4.4.15
- tar (npm): affected from 5.0.0; fixed in 5.0.7
- tar (npm): affected from 5.0.0; fixed in 5.0.7
- tar (npm): affected from 6.0.0; fixed in 6.1.2
- tar (npm): affected from 6.0.0; fixed in 6.1.2

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-32803/ (Markdown: https://insights.sbomify.com/CVE-2021-32803/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-32803
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-32803
- OSV: https://osv.dev/vulnerability/CVE-2021-32803

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-32803/
Summaries are generated and may contain mistakes; the official description above is the record.