Vulnerability from bitnami_vulndb
Published
2026-06-29 11:10
Modified
2026-06-29 11:33
Summary
tarfile extraction filter bypass allows escaping the destination directory
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.

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Bitnami",
        "name": "libpython",
        "purl": "pkg:bitnami/libpython"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "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"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-11940"
  ],
  "database_specific": {
    "cpes": [
      "cpe:2.3:a:python:python:*:*:*:*:*:*:*:*"
    ],
    "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": "BIT-libpython-2026-11940",
  "modified": "2026-06-29T11:33:52.451Z",
  "published": "2026-06-29T11:10:23.524Z",
  "references": [
    {
      "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://github.com/python/cpython/issues/151558"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/pull/151559"
    },
    {
      "type": "WEB",
      "url": "https://mail.python.org/archives/list/security-announce@python.org/thread/LD6QIISNQFQYOIEPJNEUIPV7S3V76FZH/"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-11940"
    }
  ],
  "schema_version": "1.6.2",
  "summary": "tarfile extraction filter bypass allows escaping the destination directory"
}


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