Vulnerability 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Nextcloud | Calendar | >= 5.5.13, < 5.5.17 |
Related Weaknesses (CWE)
References
- https://github.com/nextcloud/calendar/issues/7971ExploitIssue TrackingPatch
- https://github.com/nextcloud/calendar/pull/8197Issue TrackingPatch
- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-r697-7MitigationVendor Advisory
- https://hackerone.com/reports/3540663Permissions Required
FAQ
What is CVE-2026-45286?
CVE-2026-45286 is a vulnerability with a CVSS score of 4.3 (MEDIUM). 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 b...
How severe is CVE-2026-45286?
CVE-2026-45286 has been rated MEDIUM with a CVSS base score of 4.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-45286?
Check the references section above for vendor advisories and patch information. Affected products include: Nextcloud Calendar.