CVE-2025-66546

Nextcloud Calendar app allowed booking appointments without the generated token

Published Dec 5, 2025 CVSS 3.1 · 3.3 Low EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
CPEs cpe:2.3:a:nextcloud:calendar:*:*:*:*:*:*:*:*
cpe:2.3:a:nextcloud:calendar:6.0.0:-:*:*:*:*:*:*
cpe:2.3:a:nextcloud:calendar:6.0.0:rc1:*:*:*:*:*:*
cpe:2.3:a:nextcloud:calendar:6.0.0:rc2:*:*:*:*:*:*
cpe:2.3:a:nextcloud:calendar:6.0.0:rc3:*:*:*:*:*:*
cpe:2.3:a:nextcloud:calendar:6.0.0:rc4:*:*:*:*:*:*
cpe:2.3:a:nextcloud:calendar:6.0.0:rc5:*:*:*:*:*:*
cpe:2.3:a:nextcloud:calendar:6.0.0:rc6:*:*:*:*:*:*
Type Values Removed Values Added
First Time appeared Nextcloud
Nextcloud calendar
Vendors & Products Nextcloud
Nextcloud calendar
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Nextcloud Calendar app allowed booking appointments without the generated token
Weaknesses CWE-639
References
Metrics cvssV3_1

{'score': 3.3, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Dec 5, 2025, 6:32 PM
Reserved
Dec 4, 2025, 3:52 PM
Status
Analyzed
Published
Dec 5, 2025, 5:16 PM
Modified
Oct 18, 2026, 2:10 PM