Relative path traversal in zip:unzip/zip:extract via check_dir_level depth-counter bypass

{
  "id": "239a47834f1b0320f7d6c04fd449a1dd03e8e75ef8eb07bbe1f6fefe37bcbaa7",
  "url": "https://osv.dev/vulnerability/CVE-2026-47078",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Relative path traversal in zip:unzip/zip:extract via check_dir_level depth-counter bypass",
    "summary": "Relative Path Traversal vulnerability in Erlang OTP (stdlib zip module) allows writing files outside the intended extraction directory via a crafted zip archive. zip:unzip/1,2 and zip:extract/1,2 validate entry paths using zip:check_dir_level/2, which tracks directory depth as a running integer counter: .. decrements it, normal path components increment it. The caller rejects only paths where the final counter value is less than zero. A path such as ../x/y causes the counter to go negative mid-traversal then recover to zero, passing validation while resolving to a location outside the extraction directory when joined with the current working directory via add_cwd. This vulnerability is associated with program file lib/stdlib/src/zip.erl. This issue affects OTP from OTP 27.1 before OTP 27.3.4.15, OTP 28.5.0.4, and OTP 29.0.4, corresponding to stdlib from 6.1 before 6.2.2.4, 7.3.0.1, and 8.0.3.",
    "evidence": "osv:CVE-2026-47078",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-47078",
      "aliases": [
        "CVE-2026-47078",
        "EEF-CVE-2026-47078",
        "GHSA-rf72-wp7h-jg3x"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:L/SC:N/SI:L/SA:L"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/erlang/otp",
              "type": "GIT",
              "events": [
                {
                  "introduced": "8d537f51a4262d24f3395c4148323eaca9facbbd"
                },
                {
                  "fixed": "8a933c9c7835b06776d31d17b79b7336627d887a"
                },
                {
                  "introduced": "9ae2ef54fc6dacb5bfbe2dc6fc6f2522d57ce1fb"
                },
                {
                  "fixed": "8def54e66dfdd41c535272794d49cc633f596d22"
                },
                {
                  "fixed": "8d537f51a4262d24f3395c4148323eaca9facbbd"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "8d537f51a4262d24f3395c4148323eaca9facbbd"
                      },
                      {
                        "fixed": "8a933c9c7835b06776d31d17b79b7336627d887a"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "introduced": "27.1"
                      },
                      {
                        "fixed": "27.3.4.15"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "ChangesAt"
                  },
                  {
                    "range": [
                      {
                        "fixed": "8d537f51a4262d24f3395c4148323eaca9facbbd"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "8a933c9c7835b06776d31d17b79b7336627d887a"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "patch-base-27",
            "OTP-27.3.4",
            "OTP-27.3.4.9",
            "OTP-27.3.4.10",
            "OTP-27.3.4.14",
            "OTP-27.3.4.13",
            "OTP-27.3.4.12",
            "OTP-27.3.4.11",
            "OTP-27.3.4.8",
            "OTP-27.3.4.6",
            "OTP-27.3.4.7",
            "OTP-27.3",
            "OTP-27.3.4.5",
            "OTP-27.3.4.4",
            "OTP-27.3.4.3",
            "OTP-27.3.3",
            "OTP-27.3.4.2",
            "OTP-27.3.4.1",
            "OTP-27.3.2",
            "OTP-27.2",
            "OTP-27.3.1",
            "OTP-27.1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-47078.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:45.608766657Z",
      "provider": "osv",
      "references": [
        "https://cna.erlef.org/cves/CVE-2026-47078.html",
        "https://github.com",
        "https://osv.dev/vulnerability/EEF-CVE-2026-47078",
        "https://www.erlang.org/doc/system/versions.html#order-of-versions",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47078.json",
        "https://github.com/erlang/otp/security/advisories/GHSA-rf72-wp7h-jg3x",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-47078",
        "https://github.com/erlang/otp/commit/8a933c9c7835b06776d31d17b79b7336627d887a",
        "https://github.com/erlang/otp/commit/8d537f51a4262d24f3395c4148323eaca9facbbd",
        "https://github.com/erlang/otp"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-23"
        ],
        "cna_assigner": "EEF",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "6.1"
                  },
                  {
                    "fixed": "6.2.2.4"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "ChangesAt"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47078.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-47078",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 513837,
  "published_at": "2026-07-27T15:03:50.929+00:00"
}