Vulnerability Monitor

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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.

Published

2025-12-05T17:16:05.500

Last Modified

2025-12-10T14:13:30.870

Status

Analyzed

Source

[email protected]

Severity

CVSSv3.1: 5.7 (MEDIUM)

Weaknesses

Type: Secondary
CWE-241

Affected Vendors & Products

Type	Vendor	Product	Version/Range	Vulnerable?
Application	nextcloud	calendar	< 4.7.17	Yes
Application	nextcloud	calendar	< 5.2.4	Yes

References

https://github.com/nextcloud/calendar/commit/63a6c398db01391eb9fd5297a0d4c3d6e614f769 Patch ([email protected])
https://github.com/nextcloud/calendar/pull/6971 Issue Tracking ([email protected])
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f29c-ppmv-8mcv Patch, Vendor Advisory ([email protected])
https://hackerone.com/reports/3112033 Issue Tracking, Vendor Advisory ([email protected])