Vulnerability from bitnami_vulndb
Published
2026-07-12 23:47
Modified
2026-07-13 00:08
Summary
Nextcloud: Lack of authenticity of metadata keys allows a malicious server to gain access to E2EE folders
Details

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.

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Bitnami",
        "name": "nextcloud",
        "purl": "pkg:bitnami/nextcloud"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.0.5"
            },
            {
              "fixed": "4.8.0"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "severity": [
        {
          "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:L",
          "type": "CVSS_V3"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2023-28999"
  ],
  "database_specific": {
    "cpes": [
      "cpe:2.3:a:nextcloud:nextcloud:*:*:*:*:android:*:*:*",
      "cpe:2.3:a:nextcloud:nextcloud:*:*:*:*:iphone_os:*:*:*"
    ],
    "severity": "Medium"
  },
  "details": "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.\u200b 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.",
  "id": "BIT-nextcloud-2023-28999",
  "modified": "2026-07-13T00:08:34.851Z",
  "published": "2026-07-12T23:47:54.219Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://ethz.ch/content/dam/ethz/special-interest/infk/inst-infsec/appliedcrypto/education/theses/report_DanieleCoppola.pdf"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nextcloud/desktop/pull/5560"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nextcloud/security-advisories/security/advisories/GHSA-8875-wxww-3rr8"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-28999"
    }
  ],
  "schema_version": "1.6.2",
  "summary": "Nextcloud: Lack of authenticity of metadata keys allows a malicious server to gain access to E2EE folders"
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.