Description
Nextcloud is an open source content collaboration platform. From versions 5.5.13 to before 5.5.17, and 6.2.0 to before 6.2.3, an authenticated user can enumerate users on the same Nextcloud instance by using the Calendar app's endpoint for suggesting attendees. The sharing restrictions, applied to other endpoints, were not effective here. This issue has been patched in versions 5.5.17 and 6.2.3.
Metrics
CVSS 3.1 4.3/10
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:NWeakness enumeration
Affected software
| Vendor | Product | Versions |
|---|---|---|
| nextcloud | security-advisories | >= 5.5.13, < 5.5.17; >= 6.2.0, < 6.2.3 |
References
- https://github.com/nextcloud/calendar/issues/7971Exploit, Issue Tracking, Patch
- https://github.com/nextcloud/calendar/pull/8197Issue Tracking, Patch
- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-r697-74m9-gvf2Mitigation, Vendor Advisory
- https://hackerone.com/reports/3540663Permissions Required
Timeline
- Published
- Jun 1, 2026
- Last modified
- Jul 22, 2026
- NVD status
- Analyzed