Security advisory

{
  "id": "fc6b8935a24a53a2bcfd650bb407bab1cc7a0395219b82e4c3fbec02fcac6cd0",
  "url": "https://osv.dev/vulnerability/CVE-2021-32728",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-32728",
    "summary": "The Nextcloud Desktop Client is a tool to synchronize files from Nextcloud Server with a computer. Clients using the Nextcloud end-to-end encryption feature download the public and private key via an API endpoint. In versions prior to 3.3.0, the Nextcloud Desktop client fails to check if a private key belongs to previously downloaded public certificate. If the Nextcloud instance serves a malicious public key, the data would be encrypted for this key and thus could be accessible to a malicious actor. This issue is fixed in Nextcloud Desktop Client version 3.3.0. There are no known workarounds aside from upgrading.",
    "evidence": "osv:CVE-2021-32728",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2021-32728",
      "aliases": [
        "CVE-2021-32728",
        "GHSA-f5fr-5gcv-6cc5"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/nextcloud/desktop",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "acf3bf0959fc83393b71fbeed5b7633cab0f0d9d"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:nextcloud:desktop:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "3.3.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v3.3.0-rc2",
            "v3.3.0-rc1",
            "v3.2.0-rc3",
            "v3.2.0-rc2",
            "v3.2.0-rc1",
            "v3.1.0",
            "v3.1.0-rc2",
            "v3.1.0-rc1",
            "v2.7.0-rc1",
            "v2.7.0-beta3",
            "v2.7.0-beta2",
            "v2.7.0-beta1",
            "v2.5.3-rc2",
            "v2.5.3-rc1",
            "v2.5.2",
            "v2.5.2-rc1",
            "v2.5.1",
            "v2.5.0",
            "v2.5.0-rc2",
            "v2.5.0-rc1",
            "v2.5.0-beta2",
            "v2.5.0-beta1",
            "v1.8.0-beta1a",
            "v1.8.0-beta1",
            "v1.6.0",
            "v1.6.0-rc3",
            "v1.6.0-rc2",
            "v1.6.0-rc1",
            "v1.6.0-beta2",
            "v1.6.0-beta1",
            "v1.5.1-rc1",
            "v1.5.0",
            "v1.5.0-beta3",
            "v1.5.0-beta1-2nd",
            "v1.5.0-beta2",
            "v1.5.0-beta1",
            "v1.4.0",
            "v1.4.0-rc1",
            "v1.4.0-beta2",
            "v1.4.0-beta1",
            "v1.3.0-beta3",
            "v1.3.0-beta2",
            "v1.3.0-beta1",
            "v1.2.5",
            "v1.2.4",
            "v1.2.3",
            "v1.2.2",
            "v1.2.1",
            "v1.2.0",
            "v1.1.2",
            "v1.1.0",
            "v1.1.0-beta1",
            "v0.0.2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-32728.json"
          }
        }
      ],
      "modified": "2026-10-20T10:54:42.653408768Z",
      "provider": "osv",
      "references": [
        "https://www.debian.org/security/2021/dsa-4974",
        "https://github.com/nextcloud/desktop/pull/3338",
        "https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f5fr-5gcv-6cc5",
        "https://hackerone.com/reports/1189162"
      ],
      "provider_metadata": {
        "unresolved_ranges": [
          {
            "cpes": [
              "cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*",
              "cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*"
            ],
            "vendor_product": "debian:debian_linux",
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "10.0"
                  },
                  {
                    "last_affected": "10.0"
                  },
                  {
                    "introduced": "11.0"
                  },
                  {
                    "last_affected": "11.0"
                  }
                ],
                "source": "CPE_STRING"
              }
            ]
          }
        ]
      }
    },
    "related_cves": [
      {
        "value": "CVE-2021-32728",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 385956,
  "published_at": "2021-08-18T16:15:07.293+00:00"
}