#VU119259 Improper Handling of Unexpected Data Type in Nextcloud Calendar - CVE-2025-66550

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Main Vulnerability Database Vulnerabilities #VU119259

#VU119259 Improper Handling of Unexpected Data Type in Nextcloud Calendar - CVE-2025-66550

Published: December 8, 2025


Vulnerability identifier: #VU119259
Vulnerability risk: Medium
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2025-66550
CWE-ID: CWE-241
Exploitation vector: Remote access
Exploit availability: No public exploit available
Vulnerable software:
Nextcloud Calendar
Software vendor:
Nextcloud

Description

The vulnerability allows a remote attacker to compromise the target system.

The vulnerability exists due to improper handling of unexpected data type. A remote user can create a calendar event with a crafted attachment that links to a download link of a file on the same Nextcloud server and download the file without the user confirming the action.


Remediation

Install updates from vendor's website.

External links