{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:nextcloud:calendar:*:*:*:*:*:*:*:*",
            "extracted_events": [
              {
                "introduced": "4.0.0"
              },
              {
                "fixed": "4.7.17"
              },
              {
                "introduced": "5.0.0"
              },
              {
                "fixed": "5.2.4"
              }
            ],
            "source": [
              "CPE_RANGE",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "d840d46412d121c9ae2697efed7f1ce6dd414fc2"
            },
            {
              "fixed": "44423c0b8f0d903102f2bbf7a12808b8ac3da64d"
            },
            {
              "introduced": "31203fddf125223d25f3b8b0d520f567a998e8af"
            },
            {
              "fixed": "f823d93dd3ac0b759c24c769832277bf94e3081d"
            },
            {
              "fixed": "63a6c398db01391eb9fd5297a0d4c3d6e614f769"
            }
          ],
          "repo": "https://github.com/nextcloud/calendar",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-f29c-ppmv-8mcv"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-241"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/66xxx/CVE-2025-66550.json"
  },
  "details": "Nextcloud Calendar is a calendar app for Nextcloud. Prior to 4.7.17 and 5.2.4, when a malicious user creates a calendar event with a crafted attachment that links to a download link of a file on the same Nextcloud server, the file would be downloaded without the user confirming the action. This vulnerability is fixed in 4.7.17 and 5.2.4.",
  "id": "CVE-2025-66550",
  "modified": "2026-08-12T03:51:22.661522450Z",
  "published": "2025-12-05T16:56:44.680Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://hackerone.com/reports/3112033"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/66xxx/CVE-2025-66550.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f29c-ppmv-8mcv"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-66550"
    },
    {
      "type": "FIX",
      "url": "https://github.com/nextcloud/calendar/commit/63a6c398db01391eb9fd5297a0d4c3d6e614f769"
    },
    {
      "type": "FIX",
      "url": "https://github.com/nextcloud/calendar/pull/6971"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Nextcloud Calendar attachments of local files are offered to downloaded"
}