Vulnerability-Lookup

GHSA-9MC4-RQMQ-H467

Vulnerability from github – Published: 2026-06-23 18:31 – Updated: 2026-06-23 18:31

Details

tarfile.extractall() with the 'data' or 'tar' filter could be bypassed by a crafted archive where a hardlink references a symlink stored at a deeper name than the hardlink itself. The extraction fallback validated the symlink at it's archived location but recreated it at the hardlink's shallower path, letting a relative target the filter judged contained escape the destination directory. This allowed a malicious tar archive to create a symlink pointing outside the destination, enabling out-of-destination file reads or writes. This was an incomplete fix of CVE-2025-4330.

Severity

7.8 (High)


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

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-11940"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-23T17:16:40Z",
    "severity": "HIGH"
  },
  "details": "tarfile.extractall() with the \u0027data\u0027 or \u0027tar\u0027\n filter could be bypassed by a crafted archive where a hardlink \nreferences a symlink stored at a deeper name than the hardlink itself.\u00a0 \nThe extraction fallback validated the symlink at it\u0027s archived location \nbut recreated it at the hardlink\u0027s shallower\npath, letting a relative\n target the filter judged contained escape the destination directory.\u00a0 \nThis allowed a malicious tar archive to create a symlink pointing \noutside the destination, enabling out-of-destination file reads or \nwrites. This was an incomplete fix of CVE-2025-4330.",
  "id": "GHSA-9mc4-rqmq-h467",
  "modified": "2026-06-23T18:31:41Z",
  "published": "2026-06-23T18:31:41Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-11940"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/issues/151558"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/pull/151559"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/27dd970bf6b17ebca7c8ed486a40ab043ed7af8f"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/672825e2f36a57e173959b0d9d409d4560dab8df"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/771d12dda5140313db0ac550292987975651bbde"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/79c06bd5c6afa3c440d50faf7ee1b147c8832b4c"
    },
    {
      "type": "WEB",
      "url": "https://mail.python.org/archives/list/security-announce@python.org/thread/LD6QIISNQFQYOIEPJNEUIPV7S3V76FZH"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/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-2026-11940 (GCVE-0-2026-11940)

Vulnerability from cvelistv5 – Published: 2026-06-23 16:04 – Updated: 2026-06-23 17:57

Title

tarfile extraction filter bypass allows escaping the destination directory

Summary

Severity

7.8 (High)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

Assigner

PSF

References

7 references

URL	Tags
https://github.com/python/cpython/pull/151559	patch
https://mail.python.org/archives/list/security-an…	vendor-advisory
https://github.com/python/cpython/issues/151558	issue-tracking
https://github.com/python/cpython/commit/27dd970b…	patch
https://github.com/python/cpython/commit/672825e2…	patch
https://github.com/python/cpython/commit/771d12dd…	patch
https://github.com/python/cpython/commit/79c06bd5…	patch

Impacted products

1 product

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

Credits

Haruki Oyama (https://github.com/harukioya) Stan Ulbrych (https://github.com/StanFromIreland) Petr Viktorin (https://github.com/encukou)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-11940",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-23T17:57:25.652265Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-23T17:57:32.525Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "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": "Haruki Oyama (https://github.com/harukioya)"
        },
        {
          "lang": "en",
          "type": "coordinator",
          "value": "Stan Ulbrych (https://github.com/StanFromIreland)"
        },
        {
          "lang": "en",
          "type": "remediation reviewer",
          "value": "Petr Viktorin (https://github.com/encukou)"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "type": "text/html",
              "value": "\u003cspan\u003etarfile.extractall()\u003c/span\u003e with the \u003cspan\u003e\u0027data\u0027\u003c/span\u003e or \u003cspan\u003e\u0027tar\u0027\u003c/span\u003e\n filter could be bypassed by a crafted archive where a hardlink \nreferences a symlink stored at a deeper name than the hardlink itself.\u0026nbsp; \nThe extraction fallback validated the symlink at it\u0027s archived location \nbut recreated it at the hardlink\u0027s shallower\u003cbr\u003epath, letting a relative\n target the filter judged contained escape the destination directory.\u0026nbsp; \nThis allowed a malicious tar archive to create a symlink pointing \noutside the destination, enabling out-of-destination file reads or \nwrites. This was an incomplete fix of CVE-2025-4330."
            }
          ],
          "value": "tarfile.extractall() with the \u0027data\u0027 or \u0027tar\u0027\n filter could be bypassed by a crafted archive where a hardlink \nreferences a symlink stored at a deeper name than the hardlink itself.\u00a0 \nThe extraction fallback validated the symlink at it\u0027s archived location \nbut recreated it at the hardlink\u0027s shallower\npath, letting a relative\n target the filter judged contained escape the destination directory.\u00a0 \nThis allowed a malicious tar archive to create a symlink pointing \noutside the destination, enabling out-of-destination file reads or \nwrites. This was an incomplete fix of CVE-2025-4330."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "HIGH",
            "subIntegrityImpact": "HIGH",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-22",
              "description": "CWE-22",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-59",
              "description": "CWE-59",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-23T17:56:09.397Z",
        "orgId": "28c92f92-d60d-412d-b760-e73465c3df22",
        "shortName": "PSF"
      },
      "references": [
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/python/cpython/pull/151559"
        },
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://mail.python.org/archives/list/security-announce@python.org/thread/LD6QIISNQFQYOIEPJNEUIPV7S3V76FZH/"
        },
        {
          "tags": [
            "issue-tracking"
          ],
          "url": "https://github.com/python/cpython/issues/151558"
        },
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/python/cpython/commit/27dd970bf6b17ebca7c8ed486a40ab043ed7af8f"
        },
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/python/cpython/commit/672825e2f36a57e173959b0d9d409d4560dab8df"
        },
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/python/cpython/commit/771d12dda5140313db0ac550292987975651bbde"
        },
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/python/cpython/commit/79c06bd5c6afa3c440d50faf7ee1b147c8832b4c"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "tarfile extraction filter bypass allows escaping the destination directory",
      "x_generator": {
        "engine": "cvelib 1.8.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "28c92f92-d60d-412d-b760-e73465c3df22",
    "assignerShortName": "PSF",
    "cveId": "CVE-2026-11940",
    "datePublished": "2026-06-23T16:04:17.321Z",
    "dateReserved": "2026-06-10T19:50:59.923Z",
    "dateUpdated": "2026-06-23T17:57:32.525Z",
    "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.

Action not permitted

GHSA-9MC4-RQMQ-H467

CVE-2026-11940 (GCVE-0-2026-11940)

Tags

Sightings

Nomenclature