CVE-2026-33056
tar-rs `unpack_in` can chmod arbitrary directories by following symlinks
Impact
## 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!
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| rust | tar | <= 0.4.44 | 0.4.45 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Tar Project | Tar | before 0.4.45 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/alexcrichton/tar-rs/commit/17b1fd84e632071cb8eef9d3709bf347bd266446
- https://github.com/alexcrichton/tar-rs/security/advisories/GHSA-j4xf-2g29-59ph
- https://github.com/advisories/GHSA-j4xf-2g29-59ph
- https://nvd.nist.gov/vuln/detail/CVE-2026-33056
- https://rustsec.org/advisories/RUSTSEC-2026-0067.html