{"id":"CVE-2025-64011","title":"Nextcloud Server 30.0.0 is vulnerable to an Insecure Direct Object Reference (IDOR) in the /core/preview endpoint","summary":"Nextcloud Server 30.0.0 is vulnerable to an Insecure Direct Object Reference (IDOR) in the /core/preview endpoint. Any authenticated user can access previews of arbitrary files belonging to other users by manipulating the fileId paramete…","severity":"medium","cvss":4.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N","cwe":["CWE-639"],"vendor":"nextcloud","product":"nextcloud_server","affected":["nextcloud_server = 30.0.0"],"published":"2025-12-12","updated":"2026-10-14","sourceUpdated":"2026-10-14T17:10:00.210","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-64011","references":[{"url":"https://drive.google.com/file/d/1eD3PN-u1caZYgGH96XHmJ7h_OBXEAHW4/view?usp=sharing","label":"cve@mitre.org"},{"url":"https://gist.github.com/tarekramm/586dfe2d113fedfee6d71182570fc090","label":"cve@mitre.org"},{"url":"https://nextcloud.com","label":"cve@mitre.org"}],"tags":["nvd"],"epss":0.00275,"epssPercentile":0.18554,"ingestedAt":"2026-10-14T17:44:53.606Z","slug":"CVE-2025-64011","body":"## Overview\n\nNextcloud Server 30.0.0 is vulnerable to an Insecure Direct Object Reference (IDOR) in the /core/preview endpoint. Any authenticated user can access previews of arbitrary files belonging to other users by manipulating the fileId parameter. This allows unauthorized disclosure of sensitive data, such as text files or images, without prior sharing permissions.\n\n## Affected\n\n- `nextcloud_server = 30.0.0`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":24,"depthScoreParts":{"impact":23.7,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}