Description
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.
Affected products
nextcloud: calendar
References4
- github.com/nextcloud/security-advisories/security/advisories/GH… PatchVendor Advisory
- hackerone.com/reports/3275810 Issue TrackingVendor Advisory
- github.com/nextcloud/calendar/commit/f41650c3681fc4a4130eb883f5… Patch
- github.com/nextcloud/calendar/pull/7537 Issue Tracking
Metrics
- CVSS 3.1
-
3.3
LOW
Score source: CNA
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - EPSS — exploit probability
- 0% percentile: 4 · as of 11 November 2026
- CWE
- CWE-639
Could this be exploited in your environment?
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