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CVE-2021-20634

Status: ModifiedMedium (4.3)—

Improper access control vulnerability in Custom App of Cybozu Office 10.0.0 to 10.8.4 allows authenticated attackers to bypass access restriction and obtain the date of Custom App via unspecified vectors.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (1)

Cybozu — Office

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2021-20634",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 4,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:S/C:P/I:N/A:N",
          "authentication": "SINGLE",
          "integrityImpact": "NONE",
          "accessComplexity": "LOW",
          "availabilityImpact": "NONE",
          "confidentialityImpact": "PARTIAL"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 8,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 4.3,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "LOW"
        },
        "impactScore": 1.4,
        "exploitabilityScore": 2.8
      }
    ]
  },
  "affected": [
    {
      "source": "vultures@jpcert.or.jp",
      "affectedData": [
        {
          "vendor": "Cybozu, Inc.",
          "product": "Cybozu Office",
          "versions": [
            {
              "status": "affected",
              "version": "10.0.0 to 10.8.4"
            }
          ]
        }
      ]
    }
  ],
  "published": "2021-03-18T01:15:12.247",
  "references": [
    {
      "url": "https://jvn.jp/en/jp/JVN45797538/index.html",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "vultures@jpcert.or.jp"
    },
    {
      "url": "https://kb.cybozu.support/article/36865/",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "vultures@jpcert.or.jp"
    },
    {
      "url": "https://jvn.jp/en/jp/JVN45797538/index.html",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://kb.cybozu.support/article/36865/",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-Other"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Improper access control vulnerability in Custom App of Cybozu Office 10.0.0 to 10.8.4 allows authenticated attackers to bypass access restriction and obtain the date of Custom App via unspecified vectors."
    },
    {
      "lang": "es",
      "value": "Una vulnerabilidad de control de acceso inapropiado en Custom App de Cybozu Office versiones 10.0.0 hasta 10.8.4, permite a atacantes autenticados omitir la restricción de acceso y obtener la fecha de Custom App por medio de vectores no especificados"
    }
  ],
  "lastModified": "2026-06-17T03:34:09.540",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:cybozu:office:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "A468F5BE-4EB2-464F-AE29-D0C98163C410",
              "versionEndIncluding": "10.8.4",
              "versionStartIncluding": "10.0.0"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "vultures@jpcert.or.jp"
}