{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": [
              "cpe:2.3:a:nextcloud:calendar:*:*:*:*:*:*:*:*",
              "cpe:2.3:a:nextcloud:calendar:6.0.0:-:*:*:*:*:*:*"
            ],
            "extracted_events": [
              {
                "introduced": "4.0.0"
              },
              {
                "fixed": "4.7.19"
              },
              {
                "introduced": "5.0.0"
              },
              {
                "fixed": "5.5.6"
              },
              {
                "introduced": "6.0.0-NA"
              },
              {
                "last_affected": "6.0.0-NA"
              }
            ],
            "source": [
              "CPE_RANGE",
              "CPE_STRING",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "d840d46412d121c9ae2697efed7f1ce6dd414fc2"
            },
            {
              "fixed": "ee0fc1397f2cbade31712e17cabe7fd4503d3a32"
            },
            {
              "introduced": "31203fddf125223d25f3b8b0d520f567a998e8af"
            },
            {
              "fixed": "dfb76536948a4829539a61aaaa4d939afd743cb5"
            },
            {
              "introduced": "d8566e7d4dffaec2a2c4a3adcdb0be9dab2556ba"
            },
            {
              "fixed": "f41650c3681fc4a4130eb883f5c0899c011326b3"
            }
          ],
          "repo": "https://github.com/nextcloud/calendar",
          "type": "GIT"
        }
      ],
      "versions": [
        "6.0.0-NA"
      ]
    }
  ],
  "aliases": [
    "GHSA-7x2j-2674-fj95"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-639"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/66xxx/CVE-2025-66546.json"
  },
  "details": "Nextcloud Calendar is a calendar app for Nextcloud. Prior to 4.7.19, 5.5.6, and 6.0.1, the calendar app allowed blindly booking appointments with a squential ID without known the appointment token. This vulnerability is fixed in 4.7.19, 5.5.6, and 6.0.1.",
  "id": "CVE-2025-66546",
  "modified": "2026-08-12T03:51:27.113781920Z",
  "published": "2025-12-05T16:49:46.553Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://hackerone.com/reports/3275810"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/66xxx/CVE-2025-66546.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/nextcloud/security-advisories/security/advisories/GHSA-7x2j-2674-fj95"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-66546"
    },
    {
      "type": "FIX",
      "url": "https://github.com/nextcloud/calendar/commit/f41650c3681fc4a4130eb883f5c0899c011326b3"
    },
    {
      "type": "FIX",
      "url": "https://github.com/nextcloud/calendar/pull/7537"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Nextcloud Calendar app allowed booking appointments without the generated token"
}