NanaZip .NET Single-File Manifest Parser Vulnerable to Out-of-Bounds Read via Unchecked RelativePathLength

{
  "id": "67b65fd21acae012d17b8ee8be5f6f2872881dde25ed166be0f4891b8c55c0aa",
  "url": "https://osv.dev/vulnerability/CVE-2026-27709",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "NanaZip .NET Single-File Manifest Parser Vulnerable to Out-of-Bounds Read via Unchecked RelativePathLength",
    "summary": "NanaZip is an open source file archive. Starting in version 5.0.1252.0 and prior to versions 6.0.1638.0 and 6.5.1638.0, NanaZip’s `.NET Single File Application` parser has an out-of-bounds read vulnerability in manifest parsing. A crafted bundle can provide a malformed `RelativePathLength` so the parser constructs a `std::string` from memory beyond `HeaderBuffer`, leading to crash and potential in-process memory disclosure. Versions 6.0.1638.0 and 6.5.1638.0 fix the issue.",
    "evidence": "osv:CVE-2026-27709",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-27709",
      "aliases": [
        "CVE-2026-27709",
        "GHSA-vr4w-xc78-w6fv"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/m2team/nanazip",
              "type": "GIT",
              "events": [
                {
                  "introduced": "401fa98a9aeaeef137d66303ccbb442366b46e51"
                },
                {
                  "fixed": "91104bb04a5a811895143da1b9a4ad64c97dcaa3"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:m2team:nanazip:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "5.0.1252.0"
                      },
                      {
                        "fixed": "6.0.1638.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "6.0.1632.0",
            "6.0.1630.0",
            "6.0.1621.0",
            "6.0.1461.0",
            "5.1.1263.0",
            "5.0.1263.0",
            "5.1.1252.0",
            "5.0.1252.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-27709.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:53.143022377Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27709.json",
        "https://github.com/M2Team/NanaZip/security/advisories/GHSA-vr4w-xc78-w6fv",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-27709"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-125"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27709.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-27709",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 522091,
  "published_at": "2026-02-25T23:39:03.772+00:00"
}