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CVE-2023-28999

Status: ModifiedMedium (6.4)—

Nextcloud is an open-source productivity platform. In Nextcloud Desktop client 3.0.0 until 3.8.0, Nextcloud Android app 3.13.0 until 3.25.0, and Nextcloud iOS app 3.0.5 until 4.8.0, a malicious server administrator can gain full access to an end-to-end encrypted folder. They can decrypt files, recover the folder structure and add new files.​ This issue is fixed in Nextcloud Desktop 3.8.0, Nextcloud Android 3.25.0, and Nextcloud iOS 4.8.0. No known workarounds are available.

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 (2)

Nextcloud — DesktopNextcloud — Nextcloud

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2023-28999",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
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        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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          "id": "CVE-2023-28999",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
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          ],
          "version": "2.0.3",
          "timestamp": "2025-02-11T16:31:58.681356Z"
        }
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          "baseScore": 6.9,
          "attackVector": "PHYSICAL",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:P/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:L",
          "integrityImpact": "HIGH",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "LOW",
          "privilegesRequired": "HIGH",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 6,
        "exploitabilityScore": 0.4
      },
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
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          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:L",
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  "published": "2023-04-04T13:15:09.003",
  "references": [
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      "source": "af854a3a-2127-422b-91ae-364da2661108"
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  ],
  "vulnStatus": "Modified",
  "weaknesses": [
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      "type": "Secondary",
      "source": "security-advisories@github.com",
      "description": [
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          "lang": "en",
          "value": "CWE-325"
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    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
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          "lang": "en",
          "value": "CWE-311"
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  "descriptions": [
    {
      "lang": "en",
      "value": "Nextcloud is an open-source productivity platform. In Nextcloud Desktop client 3.0.0 until 3.8.0, Nextcloud Android app 3.13.0 until 3.25.0, and Nextcloud iOS app 3.0.5 until 4.8.0, a malicious server administrator can gain full access to an end-to-end encrypted folder. They can decrypt files, recover the folder structure and add new files.​ This issue is fixed in Nextcloud Desktop 3.8.0, Nextcloud Android 3.25.0, and Nextcloud iOS 4.8.0. No known workarounds are available."
    }
  ],
  "lastModified": "2026-06-17T05:49:09.567",
  "configurations": [
    {
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        {
          "negate": false,
          "cpeMatch": [
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              "versionEndExcluding": "3.8.0",
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              "versionEndExcluding": "3.25.0",
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  "sourceIdentifier": "security-advisories@github.com"
}