Vulnerability 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Nextcloud | Calendar | >= 4.0.0, < 4.7.17 |
Related Weaknesses (CWE)
References
- https://github.com/nextcloud/calendar/commit/63a6c398db01391eb9fd5297a0d4c3d6e61Patch
- https://github.com/nextcloud/calendar/pull/6971Issue Tracking
- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f29c-pPatchVendor Advisory
- https://hackerone.com/reports/3112033Issue TrackingVendor Advisory
FAQ
What is CVE-2025-66550?
CVE-2025-66550 is a vulnerability with a CVSS score of 5.7 (MEDIUM). 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 s...
How severe is CVE-2025-66550?
CVE-2025-66550 has been rated MEDIUM with a CVSS base score of 5.7/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2025-66550?
Check the references section above for vendor advisories and patch information. Affected products include: Nextcloud Calendar.