# CVE-2026-32766: astral-tokio-tar insufficiently validates PAX extensions during extraction

Source: https://junglewise.ai/threats/cve-2026-32766-astral-tokio-tar-insufficiently-validates-pax-extensions-during  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-03-17. Updated: 2026-05-11  
License: CC BY 4.0 with a link back

CVE-2026-32766 · Severity: medium · CVSS 5.3 · Published 2026-03-17

## Impact

In versions 0.5.6 and earlier of astral-tokio-tar, malformed PAX extensions were silently skipped when parsing tar archives. This silent skipping (rather than rejection) of invalid PAX extensions could be used as a building block for a parser differential, for example by having astral-tokio-tar silently skip a malformed GNU “long link” extension so that a subsequent parser would misinterpret the extension.

In practice, exploiting this behavior in astral-tokio-tar requires a secondary misbehaving tar parser, i.e. one that insufficiently validates malformed PAX extensions and interprets them rather than skipping or erroring on them. Consequently this advisory is considered low-severity within astral-tokio-tar itself, as it requires a separate vulnerability against any unrelated tar parser.

## Patches

Versions 0.6.0 and newer of astral-tokio-tar reject invalid PAX extensions, rather than silently skipping them. 

## Workarounds

Users are advised to upgrade to version 0.6.0 or newer to address this advisory.

Most users should experience no breaking changes as a result of the patch above. Some users who attempt to extract poorly constructed tar files may experience errors; users should re-construct their tar files with a conforming tar parser.

## Attribution

- Sergei Zimmerman (@xokdvium)

Technologies: [astral-tokio-tar (crates.io)](https://junglewise.ai/threats/technologies/astral-tokio-tar). Vendors: [crates.io](https://junglewise.ai/threats/vendors/crates-io).

## Quick answers

**Is CVE-2026-32766 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-32766 being exploited in the wild.

**How severe is CVE-2026-32766?** Medium severity, with a CVSS score of 5.3, published 17 March 2026.

**Which products and versions are affected?** astral-tokio-tar (crates.io) <= 0.5.6, SEMVER:introduced=0,fixed=0.6.0, SEMVER:introduced=0.0.0-0,fixed=0.6.0.

**Is there a fix for CVE-2026-32766?** Yes. astral-tokio-tar (crates.io): upgrade to 0.6.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2026-32766?** Check whether you run astral-tokio-tar (crates.io) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- astral-tokio-tar (crates.io): upgrade to 0.6.0 or later

  ```sh
  cargo update -p astral-tokio-tar
  ```


## Affected products

- astral-tokio-tar (crates.io) <= 0.5.6, SEMVER:introduced=0,fixed=0.6.0, SEMVER:introduced=0.0.0-0,fixed=0.6.0

## Identifiers

- CVE-2026-32766
- GHSA-6gx3-4362-rf54
- RUSTSEC-2026-0066

## References

- [https://api.github.com/users/woodruffw](https://api.github.com/users/woodruffw)
- [https://github.com/woodruffw](https://github.com/woodruffw)
- [https://api.github.com/users/woodruffw/gists%7B/gist_id%7D](https://api.github.com/users/woodruffw/gists%7B/gist_id%7D)
- [https://api.github.com/users/woodruffw/repos](https://api.github.com/users/woodruffw/repos)
- [https://avatars.githubusercontent.com/u/3059210?v=4](https://avatars.githubusercontent.com/u/3059210?v=4)
- [https://api.github.com/users/woodruffw/events%7B/privacy%7D](https://api.github.com/users/woodruffw/events%7B/privacy%7D)

## Related threats

- [Astral astral-tokio-tar library unmaintained](https://junglewise.ai/threats/rustsec-2026-0440-astral-tokio-tar-is-unmaintained-9bf9b77f)
- [Astral astral-tokio-tar PAX header desynchronization](https://junglewise.ai/threats/astral-astral-tokio-tar-pax-header-desynchronization-c2fb9068)
- [RUSTSEC-2026-0145 - PAX Header Desynchronization in astral-tokio-tar](https://junglewise.ai/threats/rustsec-2026-0145-pax-header-desynchronization-in-astral-tokio-tar-01625d48)
- [astral-tokio-tar: `unpack_in` can chmod arbitrary directories by following symlinks](https://junglewise.ai/threats/astral-tokio-tar-unpack-in-can-chmod-arbitrary-directories-by-following-6d2f1c09)
- [astral-tokio-tar is Vulnerable to PAX Header Desynchronization](https://junglewise.ai/threats/astral-tokio-tar-is-vulnerable-to-pax-header-desynchronization-a46fcefa)