{"id":"CVE-2025-66550","aliases":["EUVD-2025-201443","GHSA-f29c-ppmv-8mcv"],"status":"published","title":"Nextcloud Calendar attachments of local files are offered to downloaded","description":"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.","severity":{"version":"3.1","score":5.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00366,"percentile":0.3069,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-241"],"published":"2025-12-05T16:56:44Z","modified":"2026-10-28T02:31:06Z","products":[{"vendor":"kiteworks","product":"security-advisories"},{"vendor":"nextcloud","product":"calendar"},{"vendor":"nextcloud","product":"security-advisories"}],"references":[{"url":"https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f29c-ppmv-8mcv","tags":["x_refsource_CONFIRM","Patch","Vendor Advisory","advisory"]},{"url":"https://github.com/nextcloud/calendar/pull/6971","tags":["x_refsource_MISC","Issue Tracking","fix"]},{"url":"https://github.com/nextcloud/calendar/commit/63a6c398db01391eb9fd5297a0d4c3d6e614f769","tags":["x_refsource_MISC","Patch","fix"]},{"url":"https://hackerone.com/reports/3112033","tags":["x_refsource_MISC","Issue Tracking","Vendor Advisory","web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/66xxx/CVE-2025-66550.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2025-66550","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2025-66550","title":"Nextcloud Calendar attachments of local files are offered to downloaded","description":"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.","status":"published","published":"2025-12-05T16:56:44.68Z","modified":"2025-12-05T18:41:24.347Z","cvss":[{"version":"3.1","score":5.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-241"],"updated_at":"2026-11-02T14:32:53.157279Z"}],"euvd":[{"id":"EUVD-2025-201443","description":"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.","status":"published","published":"2025-12-05T16:56:44Z","modified":"2025-12-05T18:41:24Z","cvss":[{"version":"3.1","score":5.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N","level":"medium"}],"updated_at":"2026-11-02T19:49:09.437744Z"}],"nvd":[{"id":"CVE-2025-66550","description":"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.","status":"published","published":"2025-12-05T17:16:05.5Z","modified":"2026-10-18T14:10:00.11Z","cvss":[{"version":"3.1","score":5.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-241"],"updated_at":"2026-11-02T14:11:49.093461Z"}],"osv":[{"id":"CVE-2025-66550","title":"Nextcloud Calendar attachments of local files are offered to downloaded","description":"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.","status":"published","published":"2025-12-05T16:56:44.68Z","modified":"2026-10-28T02:31:06.083340237Z","cvss":[{"version":"3.1","score":5.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N","level":"medium"}],"cwes":["CWE-241"],"updated_at":"2026-11-02T15:44:52.202386Z"}]}}