CVE-2025-66546
December 05, 2025
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 Packages
https://github.com/nextcloud/calendar.git (GITHUB):
Affected version(s) >=v1.0-alpha1 <v4.7.19Fix Suggestion:
Update to version v4.7.19https://github.com/nextcloud/calendar.git (GITHUB):
Affected version(s) >=v5.0.0 <v5.5.6Fix Suggestion:
Update to version v5.5.6https://github.com/nextcloud/calendar.git (GITHUB):
Affected version(s) =v6.0.0 <v6.0.1Fix Suggestion:
Update to version v6.0.1Related Resources (4)
Do you need more information?
Contact UsCVSS v4
Base Score:
4.8
Attack Vector
LOCAL
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
LOW
User Interaction
NONE
Vulnerable System Confidentiality
LOW
Vulnerable System Integrity
NONE
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
3.3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Weakness Type (CWE)
Authorization Bypass Through User-Controlled Key
EPSS
Base Score:
0.01
