CVE-2026-55781

{
  "id": "CVE-2026-55781",
  "sourceIdentifier": "[email protected]",
  "published": "2026-07-10T17:16:59.883",
  "lastModified": "2026-10-25T15:10:00.147",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "NanaZip is the 7-Zip derivative intended for the modern Windows experience. Prior to 6.5.1749.0, NanaZip's UFS and FFS image handler in NanaZip.Codecs.Archive.Ufs.cpp validates the superblock block size only against the MINBSIZE lower bound and does not validate the fs_fsize fragment size, allowing attacker-controlled 32-bit fields to flow into indirect-block, directory, and extraction buffer allocations. A tiny crafted UFS image can force multi-gigabyte allocations during open or extraction, causing memory exhaustion or process termination. This issue is fixed in version 6.5.1749.0."
    },
    {
      "lang": "es",
      "value": "NanaZip es el derivado de 7-Zip destinado a la experiencia moderna de Windows. Antes de la versión 6.5.1749.0, el gestor de imágenes UFS y FFS de NanaZip en NanaZip.Codecs.Archive.Ufs.cpp valida el tamaño de bloque del superbloque solo contra el límite inferior MINBSIZE y no valida el tamaño de fragmento fs_fsize, permitiendo que campos de 32 bits controlados por el atacante fluyan hacia asignaciones de búfer de bloque indirecto, directorio y extracción. Una pequeña imagen UFS manipulada puede forzar asignaciones de varios gigabytes durante la apertura o extracción, causando agotamiento de memoria o terminación del proceso. Este problema está solucionado en la versión 6.5.1749.0."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "M2Team",
          "product": "NanaZip",
          "versions": [
            {
              "version": "< 6.5.1749.0",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV40": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "4.0",
          "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/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": 2.4,
          "baseSeverity": "LOW",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "privilegesRequired": "LOW",
          "userInteraction": "PASSIVE",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "vulnAvailabilityImpact": "LOW",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "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": "2026-07-10T20:46:24.470182Z",
          "id": "CVE-2026-55781",
          "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-400"
        },
        {
          "lang": "en",
          "value": "CWE-789"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/M2Team/NanaZip/commit/6415b6bff70bc9c486b49cbbc1982724c67f8338",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/M2Team/NanaZip/releases/tag/6.5.1749.0",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/M2Team/NanaZip/security/advisories/GHSA-m34h-jf84-m74h",
      "source": "[email protected]"
    }
  ]
}