astral-tokio-tar has a PAX Header Desynchronization issue

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

6.9 · 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 · score source

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Impact Versions of astral-tokio-tar prior to 0.6.2 contain a PAX header interpretation bug that allows manipulated entries to be made selectively visible or invisible during extraction with astral-tokio-tar versus other tar implementations. An attacker could use this differential to smuggle unexpected files onto a victim's filesystem. Details When a tar stream contains multiple "header" entries prior to a file entry, astral-tokio-tar applies the PAX header (x) to the next entry in the stream, regardless of type. For example, a stream of x - L - file (PAX, GNU longname, file) would result in x's extensions being applied to L rather than to file. Per POSIX pax, this is incorrect: a PAX header always applies to a file entry, not any intermediary entries. See the "pax Header Block" section for the specific prescription there. As a result of this, an attacker can contrive a tar containing a sequence of tar headers such that astral-tokio-tar applies the PAX header's size extension to the…

Published by the source

29 May 2026, 19:08 UTC

Last modified by the source

29 May 2026, 19:08 UTC

Source last checked

26 Oct 2026, 15:42 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-3cv2-h65g-fgmm

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# Patch Next advisory brief: GHSA-3cv2-h65g-fgmm

Advisory: astral-tokio-tar has a PAX Header Desynchronization issue
IDs: GHSA-3cv2-h65g-fgmm
Record: https://patchnext.com/advisories/ghsa-3cv2-h65g-fgmm (revision 1, source checked 26 Oct 2026, 15:42 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: astral-tokio-tar 0.6.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io astral-tokio-tar: affected <= 0.6.1; fixed in 0.6.2

## Suggested inspection (read-only)
- crates.io astral-tokio-tar: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on astral-tokio-tar.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-3cv2-h65g-fgmm (GitHub-reviewed advisory GHSA-3cv2-h65g-fgmm lists affected ranges: crates.io astral-tokio-tar >=0 <=0.6.1)

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