astral-tokio-tar: `unpack_in` can chmod arbitrary directories by following symlinks

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

### 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)

Source published

6 May 2026 17:26:38 UTC

Source modified

10 Sep 2026 03:51:07 UTC

Observed here

24 Oct 2026 13:19:54 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U

Publisher rating · LOW

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.

Source published

27 Apr 2026 12:00:00 UTC

Source modified

12 Oct 2026 18:00:09 UTC

Observed here

24 Oct 2026 13:19:54 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.