CVE-2025-66550 | Nextcloud Calendar up to 4.7.16/5.2.3 Attachment unexpected data type

December 5, 2025 Yanac

A vulnerability identified as problematic has been detected in Nextcloud Calendar up to 4.7.16/5.2.3. This issue affects some unknown processing of the component Attachment Handler. This manipulation causes improper handling of unexpected data type.

This vulnerability is registered as CVE-2025-66550. Remote exploitation of the attack is possible. No exploit is available.

You should upgrade the affected component.VulDB Recent EntriesRead More