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CVE-2026-66484

Full vulnerability record from the local CVENow database.

Description

GNU cpio contains a Path Traversal vulnerability in its tar archive extraction functionality. When extracting a tar archive in copy-in mode with the --no-absolute-filenames option, the extracted file name is normalized but the tar hard-link target is passed to the link_to_name function without equivalent sanitization before calling link function. A tar archive provided by an attacker, containing a hard-link entry whose linkname is set to an absolute path outside the extraction directory, can cause cpio to create a hard link to an existing file outside the intended extraction directory, breaking the expected guarantee of --no-absolute-filenames and allowing archive-controlled linkage to external files. This issue has been fixed in commit e2b9cbdd3354d2b1569b7390d1bc15c1930559ad

Severity
MEDIUM
CVSS score
4.6 (v4.0)
Vulnerability status
Deferred
Source identifier
Published
2026-08-10 11:17:27.620000
Last modified
2026-10-24 16:10:00.153000
View original CVE JSON
{
  "id": "CVE-2026-66484",
  "sourceIdentifier": "[email protected]",
  "published": "2026-08-10T11:17:27.620",
  "lastModified": "2026-10-24T16:10:00.153",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "GNU cpio contains a Path Traversal vulnerability in its tar archive extraction functionality. When extracting a tar archive in copy-in mode with the --no-absolute-filenames option, the extracted file name is normalized but the tar hard-link target is passed to the link_to_name function without equivalent sanitization before calling link function. A tar archive provided by an attacker, containing a hard-link entry whose linkname is set to an absolute path outside the extraction directory, can cause cpio to create a hard link to an existing file outside the intended extraction directory, breaking the expected guarantee of --no-absolute-filenames and allowing archive-controlled linkage to external files.\n\nThis issue has been fixed in commit e2b9cbdd3354d2b1569b7390d1bc15c1930559ad"
    },
    {
      "lang": "es",
      "value": "GNU cpio contiene una vulnerabilidad de salto de ruta en su funcionalidad de extracción de archivos tar. Al extraer un archivo tar en modo de copia de entrada (copy-in mode) con la opción --no-absolute-filenames, el nombre del archivo extraído se normaliza, pero el objetivo del enlace duro (hard-link target) de tar se pasa a la función link_to_name sin una sanitización equivalente antes de llamar a la función link. Un archivo tar proporcionado por un atacante, que contiene una entrada de enlace duro (hard-link entry) cuyo linkname está configurado a una ruta absoluta fuera del directorio de extracción, puede hacer que cpio cree un enlace duro a un archivo existente fuera del directorio de extracción previsto, rompiendo la garantía esperada de --no-absolute-filenames y permitiendo el enlace controlado por el archivo a archivos externos.\n\nEste problema ha sido solucionado en el commit e2b9cbdd3354d2b1569b7390d1bc15c1930559ad"
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "GNU",
          "product": "cpio",
          "defaultStatus": "unaffected",
          "programFiles": [
            "tar.c"
          ],
          "repo": "https://git.savannah.gnu.org/cgit/cpio.git",
          "versions": [
            {
              "version": "0",
              "lessThanOrEqual": "2.15",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV40": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "4.0",
          "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:L/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",
          "baseScore": 4.6,
          "baseSeverity": "MEDIUM",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "privilegesRequired": "NONE",
          "userInteraction": "ACTIVE",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "LOW",
          "vulnAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "LOW",
          "subAvailabilityImpact": "NONE",
          "exploitMaturity": "NOT_DEFINED",
          "confidentialityRequirement": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "valueDensity": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "providerUrgency": "NOT_DEFINED"
        }
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-08-10T10:57:05.821880Z",
          "id": "CVE-2026-66484",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-22"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://cert.pl/en/posts/2026/08/CVE-2026-66484",
      "source": "[email protected]"
    },
    {
      "url": "https://git.savannah.gnu.org/cgit/cpio.git",
      "source": "[email protected]"
    }
  ]
}