Path Traversal in GNU cpio

{
  "id": "61b0ac933f066eb59f7f8987ff31621589caa2222b4616d99f5d906b308aa74c",
  "url": "https://osv.dev/vulnerability/CVE-2026-66484",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Path Traversal in GNU cpio",
    "summary": "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",
    "evidence": "osv:CVE-2026-66484",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-66484",
      "aliases": [
        "CVE-2026-66484"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "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"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.savannah.gnu.org/cgit/cpio.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "e2b9cbdd3354d2b1569b7390d1bc15c1930559ad"
                }
              ],
              "database_specific": {
                "extracted_events": [
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                    "range": [
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                        "introduced": "0"
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                      {
                        "fixed": "e2b9cbdd3354d2b1569b7390d1bc15c1930559ad"
                      }
                    ],
                    "source": "DESCRIPTION"
                  },
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "e2b9cbdd3354d2b1569b7390d1bc15c1930559ad"
                      }
                    ],
                    "source": "DESCRIPTION"
                  }
                ]
              }
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-66484.json"
          }
        }
      ],
      "modified": "2026-10-25T02:30:52.377050171Z",
      "provider": "osv",
      "references": [
        "https://cert.pl/en/posts/2026/08/CVE-2026-66484",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66484.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-66484",
        "https://git.savannah.gnu.org/cgit/cpio.git"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-22"
        ],
        "cna_assigner": "CERT-PL",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "last_affected": "2.15"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          },
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "last_affected": "2.15"
                  }
                ],
                "source": "CPE_FIELD",
                "strategy": "CPEApplicability"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66484.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-66484",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 444563,
  "published_at": "2026-08-10T10:25:27.901+00:00"
}