astral-tokio-tar: `unpack_in` can chmod arbitrary directories by following symlinks
Date: 2026-05
Affected: rust/astral-tokio-tar
Attack vector: other
Category: vulnerability-disclosure
Severity: Low
CWE: CWE-61

### Impact In versions 0.6.0 and earlier of astral-tokio-tar, the `unpack_in` API could inadvertently modify the permissions of external (i.e. non-archive) directories outside of the archive. An attacker could use this to contrite a tar archive that maliciously changes directory permissions outside of its intended hierarchy. This flaw only affects directories; individual file permissions cannot be modified via it. See GHSA-j4xf-2g29-59ph for the equivalent flaw in the `tar` crate. ### Patches Versions 0.6.1 and newer of astral-tokio-tar use `fs::symlink_metdata` rather than `fs::metadata`, avoiding the traversal. ### Workarounds Users are advised to upgrade to version 0.6.1 or newer to address this advisory. Users should experience no breaking changes as a result of the patch above. ### Resources - GHSA-j4xf-2g29-59ph for the original `tar` vulnerability ### Attribution - Reporter: Adam Harvey (@lawngnome)


Mitigations:

Architectural layers (MAESTRO):