GHSA-j4xf-2g29-59ph

Source

https://github.com/advisories/GHSA-j4xf-2g29-59ph

Import Source

https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-j4xf-2g29-59ph/GHSA-j4xf-2g29-59ph.json

JSON Data

https://api.test.osv.dev/v1/vulns/GHSA-j4xf-2g29-59ph

Aliases

Related

CGA-8xvq-x5ff-4hpp

Published

2026-03-20T17:25:09Z

Modified

2026-03-23T19:29:13.465622Z

Severity

5.1 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N CVSS Calculator

Summary

tar-rs `unpack_in` can chmod arbitrary directories by following symlinks

Details

Summary

When unpacking a tar archive, the tar crate's unpack_dir function uses fs::metadata() to check whether a path that already exists is a directory. Because fs::metadata() follows symbolic links, a crafted tarball containing a symlink entry followed by a directory entry with the same name causes the crate to treat the symlink target as a valid existing directory — and subsequently apply chmod to it. This allows an attacker to modify the permissions of arbitrary directories outside the extraction root.

Reproducer

A malicious tarball contains two entries: (1) a symlink foo pointing to an arbitrary external directory, and (2) a directory entry foo/. (or just foo). When unpacked, create_dir("foo") fails with EEXIST because the symlink is already on disk. The fs::metadata() check then follows the symlink, sees a directory at the target, and allows processing to continue. The directory entry's mode bits are then applied via chmod, which also follows the symlink — modifying the permissions of the external target directory.

Fix

The fix is very simple, we now use fs::symlink_metadata() in unpack_dir, so symlinks are detected and rejected rather than followed.

Credit

This issue was reported by @xokdvium - thank you!

Database specific

{
    "severity": "MODERATE",
    "nvd_published_at": "2026-03-20T08:16:11Z",
    "cwe_ids": [
        "CWE-61"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-20T17:25:09Z"
}

References

Affected packages

crates.io / tar

Package

Name: tar; View open source insights on deps.dev
Purl: pkg:cargo/tar

Affected ranges

Type: SEMVER
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

0.4.45

Database specific

source

"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-j4xf-2g29-59ph/GHSA-j4xf-2g29-59ph.json"

last_known_affected_version_range

"<= 0.4.44"