CVE-2026-32766: Astral tokio tar Astral-tokio-tar Insufficiently Validates PAX Extensions Vulnerability

MODERATE
Advisory Identifier: GHSA-6gx3-4362-rf54
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CVSS 5.3
CWE-436
Published
Advisory Summary

CVE-2026-32766 is a MODERATE (CVSS 5.3) astral-tokio-tar insufficiently validates pax extensions vulnerability (CWE-436: Interpretation Conflict) affecting Astral tokio tar libraries in the crates.io ecosystem. The issue involves astral-tokio-tar insufficiently validates pax extensions during extraction. Remediation is available by upgrading affected packages to version 0.6.0.

CVE-2026-32766 at a Glance

CVE Identifier CVE-2026-32766
GHSA Identifier GHSA-6gx3-4362-rf54
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-436: Interpretation Conflict
Affected Product Astral tokio tar
Package Ecosystem crates.io
Published Date
Last Updated

Security Impact

CVSS: 5.3

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2026-32766

To remediate this vulnerability, upgrade all affected Astral tokio tar dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

astral-tokio-tar fixed: 0.6.0 
Upgrade astral-tokio-tar to 0.6.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for astral-tokio-tar

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-32766, inspect your project dependencies for Astral tokio tar:

inspect dependencies for astral-tokio-tar

Analyze the terminal output to locate any version of Astral tokio tar in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.6.0), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-436: Interpretation Conflict, where product a handles inputs or steps differently than product b, which causes a to perform incorrect actions based on its perception of b's state. In Astral tokio tar, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

## 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)

CVE-2026-32766 Affected Astral tokio tar Versions

1 component(s)
Fixed Versions:
0.6.0
Product / Package Ecosystem Affected Versions Fixed Version
astral-tokio-tar
 crates.io
< 0.6.0
0.6.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/astral-sh/tokio-tar/security/advisories/GHSA-6gx3-4362-rf54
NVD — CVE-2026-32766 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-32766
Security Fix Commit FIX COMMIT
https://github.com/astral-sh/tokio-tar/commit/e5e0139cae4577eeedf5fc16b65e690bf988ce52
Astral tokio tar Source Repository REPOSITORY
https://github.com/astral-sh/tokio-tar
rustsec.org/advisories/rustsec-... WEB
https://rustsec.org/advisories/RUSTSEC-2026-0066.html

Frequently Asked Questions

What is CVE-2026-32766?
CVE-2026-32766 is a security vulnerability in Astral tokio tar involving astral-tokio-tar insufficiently validates PAX extensions during extraction under CWE-436: Interpretation Conflict.
Which Astral tokio tar versions are affected?
Affected versions include releases prior to 0.6.0 across affected packages: astral-tokio-tar.
What version fixes CVE-2026-32766?
Upgrading to 0.6.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is astral-tokio-tar affected?
Yes, astral-tokio-tar is affected in releases prior to 0.6.0. Upgrade your dependency to 0.6.0 or later.
What is the CVSS score of CVE-2026-32766?
CVE-2026-32766 has a CVSS v3.1 base score of 5.3 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.
What CWE is associated with CVE-2026-32766?
CVE-2026-32766 is classified under CWE-436: Interpretation Conflict (Product A handles inputs or steps differently than Product B, which causes A to perform incorrect actions based on its perception of B's state.).
How can I check crates.io dependencies for CVE-2026-32766?
Run the dependency tree command: 'inspect dependencies for astral-tokio-tar'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-6gx3-4362-rf54",
  "modified" : "2026-04-24T20:45:41Z",
  "published" : "2026-03-17T19:49:35Z",
  "aliases" : [ "CVE-2026-32766" ],
  "summary" : "astral-tokio-tar insufficiently validates PAX extensions during extraction",
  "details" : "## Impact\n\nIn 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.\n\nIn 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.\n\n## Patches\n\nVersions 0.6.0 and newer of astral-tokio-tar reject invalid PAX extensions, rather than silently skipping them. \n\n## Workarounds\n\nUsers are advised to upgrade to version 0.6.0 or newer to address this advisory.\n\nMost 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.\n\n## Attribution\n\n- Sergei Zimmerman (@xokdvium)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "astral-tokio-tar"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.6.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.5.6"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/astral-sh/tokio-tar/security/advisories/GHSA-6gx3-4362-rf54"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-32766"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/astral-sh/tokio-tar/commit/e5e0139cae4577eeedf5fc16b65e690bf988ce52"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/astral-sh/tokio-tar"
  }, {
    "type" : "WEB",
    "url" : "https://rustsec.org/advisories/RUSTSEC-2026-0066.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-436" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-17T19:49:35Z",
    "nvd_published_at" : "2026-03-20T00:16:18Z"
  }
}