Vulnerability-Lookup

GHSA-RJ44-3777-MH5X

Vulnerability from github – Published: 2026-09-11 18:31 – Updated: 2026-09-12 03:30

Details

When tarfile extracts a link on a system that doesn't support links, it falls back to extracting a member from the archive. In this case, the filter function is run twice: once for the extracted member, and once with name set to the location of the link. For one of the calls, the return value was ignored. Instead, the member should be skipped if either call returns None.

Severity

5.7 (Medium)


                  
                    CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

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{
  "affected": [],
  "aliases": [
    "CVE-2026-87910"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-11T18:16:59Z",
    "severity": "MODERATE"
  },
  "details": "When tarfile extracts a link on a system that doesn\u0027t support links, it falls back to extracting a member from the archive. In this case, the filter function is run twice: once for the extracted member, and once with name set to the location of the link. For one of the calls, the return value was ignored. Instead, the member should be skipped if either call returns None.",
  "id": "GHSA-rj44-3777-mh5x",
  "modified": "2026-09-12T03:30:22Z",
  "published": "2026-09-11T18:31:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-87910"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/issues/157265"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/pull/157266"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/d9565e54b1fc6d63c5be9afd58114499128fa57b"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/fb2f0bbc3b35264f09cc2cb2934b7987527a6bc2"
    },
    {
      "type": "WEB",
      "url": "https://mail.python.org/archives/list/security-announce@python.org/thread/57TBTLL2W6APMZR3A25B2YV7GL3EPTDJ"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/09/11/8"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-87910 (GCVE-0-2026-87910)

Vulnerability from cvelistv5 – Published: 2026-09-11 17:27 – Updated: 2026-09-12 00:31

Title

tarfile hardlink fallback ignores custom extraction filter rejection via None

Summary

Severity

5.7 (Medium)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-11 19:23 UTC

CWE

Assigner

PSF mitre root

References

6 references

URL	Tags
https://mail.python.org/archives/list/security-an…	vendor-advisory
https://github.com/python/cpython/pull/157266	patch
https://github.com/python/cpython/issues/157265	issue-tracking
https://github.com/python/cpython/commit/d9565e54…	patch
https://github.com/python/cpython/commit/fb2f0bbc…	patch
http://www.openwall.com/lists/oss-security/2026/09/11/8

Impacted products

1 product

Vendor	Product	Version
Python Software Foundation	CPython	Affected: 0 , < 3.15.0 (python)

Credits

William Woodruff (https://github.com/woodruffw) Zanie Blue (https://github.com/zanieb) Petr Viktorin (https://github.com/encukou) Stan Ulbrych (https://github.com/StanFromIreland)

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JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-87910",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-11T19:23:39.973519Z",
                "version": "2.0.3"
              },
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        "providerMetadata": {
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          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2026-09-11T21:07:14.642Z",
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        "references": [
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            "url": "http://www.openwall.com/lists/oss-security/2026/09/11/8"
          }
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        "title": "CVE Program Container"
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          "defaultStatus": "unaffected",
          "product": "CPython",
          "repo": "https://github.com/python/cpython",
          "vendor": "Python Software Foundation",
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        },
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          "type": "finder",
          "value": "Zanie Blue (https://github.com/zanieb)"
        },
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          "type": "coordinator",
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        },
        {
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          "type": "remediation reviewer",
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      "metrics": [
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            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
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            "attackVector": "NETWORK",
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            "exploitMaturity": "NOT_DEFINED",
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            "providerUrgency": "NOT_DEFINED",
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      "title": "tarfile hardlink fallback ignores custom extraction filter rejection via None",
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    "datePublished": "2026-09-11T17:27:04.339Z",
    "dateReserved": "2026-09-09T15:11:08.270Z",
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

GHSA-RJ44-3777-MH5X

CVE-2026-87910 (GCVE-0-2026-87910)

Tags

Sightings

Nomenclature