Vulnerability-Lookup

Vulnerability from bitnami_vulndb

Published

2026-09-17 11:54

Modified

2026-09-17 12:08

Summary

tarfile hardlink fallback ignores custom extraction filter rejection via None

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.

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Bitnami",
        "name": "python",
        "purl": "pkg:bitnami/python"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "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"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-87910"
  ],
  "database_specific": {
    "cpes": [
      "cpe:2.3:a:python:python:*:*:*:*:*:*:*:*"
    ],
    "severity": "Medium"
  },
  "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": "BIT-python-2026-87910",
  "modified": "2026-09-17T12:08:03.261Z",
  "published": "2026-09-17T11:54:23.295Z",
  "references": [
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/09/11/8"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/d9565e54b1fc6d63c5be9afd58114499128fa57b"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/fb2f0bbc3b35264f09cc2cb2934b7987527a6bc2"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/issues/157265"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/pull/157266"
    },
    {
      "type": "WEB",
      "url": "https://mail.python.org/archives/list/security-announce@python.org/thread/57TBTLL2W6APMZR3A25B2YV7GL3EPTDJ/"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-87910"
    }
  ],
  "schema_version": "1.6.2",
  "summary": "tarfile hardlink fallback ignores custom extraction filter rejection via None"
}

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)

Show details on NVD website

JSON

To clipboard

{
  "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"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-11T19:23:49.726Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2026-09-11T21:07:14.642Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/09/11/8"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "CPython",
          "repo": "https://github.com/python/cpython",
          "vendor": "Python Software Foundation",
          "versions": [
            {
              "lessThan": "3.15.0",
              "status": "affected",
              "version": "0",
              "versionType": "python"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "William Woodruff (https://github.com/woodruffw)"
        },
        {
          "lang": "en",
          "type": "finder",
          "value": "Zanie Blue (https://github.com/zanieb)"
        },
        {
          "lang": "en",
          "type": "coordinator",
          "value": "Petr Viktorin (https://github.com/encukou)"
        },
        {
          "lang": "en",
          "type": "remediation reviewer",
          "value": "Stan Ulbrych (https://github.com/StanFromIreland)"
        }
      ],
      "descriptions": [
        {
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          "supportingMedia": [
            {
              "type": "text/html",
              "value": "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."
            }
          ],
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        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 5.7,
            "baseSeverity": "MEDIUM",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "LOW",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "ACTIVE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "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",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "HIGH",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
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      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-22",
              "description": "CWE-22",
              "lang": "en",
              "type": "CWE"
            },
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              "description": "CWE-59",
              "lang": "en",
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      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-12T00:31:42.680Z",
        "orgId": "28c92f92-d60d-412d-b760-e73465c3df22",
        "shortName": "PSF"
      },
      "references": [
        {
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          "url": "https://mail.python.org/archives/list/security-announce@python.org/thread/57TBTLL2W6APMZR3A25B2YV7GL3EPTDJ/"
        },
        {
          "tags": [
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        },
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        },
        {
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          "url": "https://github.com/python/cpython/commit/d9565e54b1fc6d63c5be9afd58114499128fa57b"
        },
        {
          "tags": [
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          "url": "https://github.com/python/cpython/commit/fb2f0bbc3b35264f09cc2cb2934b7987527a6bc2"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "tarfile hardlink fallback ignores custom extraction filter rejection via None",
      "x_generator": {
        "engine": "cvelib 1.8.0"
      }
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  },
  "cveMetadata": {
    "assignerOrgId": "28c92f92-d60d-412d-b760-e73465c3df22",
    "assignerShortName": "PSF",
    "cveId": "CVE-2026-87910",
    "datePublished": "2026-09-11T17:27:04.339Z",
    "dateReserved": "2026-09-09T15:11:08.270Z",
    "dateUpdated": "2026-09-12T00:31:42.680Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.