CVE-2025-66514

Nextcloud Mail prior to version 5.5.3 contains a stored HTML injection issue in the message list that lets an authenticated user inject HTML into email subjects. The Nextcloud Server content security policy blocks Javascript, which mitigates some risk. The issue is addressed by upgrading to Nextc...

CVE-2025-66514 Nextcloud Mail stored HTML injection in subject text

Nextcloud Mail is the mail app for Nextcloud, a self-hosted productivity platform. Prior to 5.5.3, a stored HTML injection in the Mail app's message list allowed an authenticated user to inject HTML into the email subjects. Javascript was correctly blocked by the content security policy of the...