VULNERABILITY INTELLIGENCE

CVE-2025-66550

CVSS score5.7 MEDIUM

EPSS probability0.34%

CISA KEVNot currently listed

Published2025-12-05

Last modified2026-10-18

Description

Nextcloud Calendar is a calendar app for Nextcloud. Prior to 4.7.17 and 5.2.4, when a malicious user creates a calendar event with a crafted attachment that links to a download link of a file on the same Nextcloud server, the file would be downloaded without the user confirming the action. This vulnerability is fixed in 4.7.17 and 5.2.4.