CVE-2025-66550

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.

CVSS v3 5.7 MEDIUM

5.7^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.1 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction REQUIRED

Confidentiality Impact NONE

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/nextcloud/calendar/commit/63a6c398db01391eb9fd5297a0d4c3d6e614f769	Patch
https://github.com/nextcloud/calendar/pull/6971	Issue Tracking
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f29c-ppmv-8mcv	Patch Vendor Advisory
https://hackerone.com/reports/3112033	Issue Tracking Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:nextcloud:calendar::::::::
	cpe:2.3:a:nextcloud:calendar::::::::

History

No history.

Information

Published : 2025-12-05 17:16

Updated : 2025-12-10 14:13

NVD link : CVE-2025-66550

Mitre link : CVE-2025-66550

CVE.ORG link : CVE-2025-66550

JSON object : View

Products Affected

nextcloud

calendar

CWE

CWE-241

Improper Handling of Unexpected Data Type

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