A missing check for IPv4 nested inside IPv6 in Nextcloud server < 17.0.1, < 16.0.7, and < 15.0.14 allowed a Server-Side Request Forgery (SSRF) vulnerability when subscribing to a malicious calendar URL.
A missing access control check in Nextcloud Server < 18.0.1, < 17.0.4, and < 16.0.9 causes hide-download shares to be downloadable when appending /download to the URL.
A code injection in Nextcloud Desktop Client 2.6.2 for macOS allowed to load arbitrary code when starting the client with DYLD_INSERT_LIBRARIES set in the environment.
An authenticated server-side request forgery in Nextcloud server 16.0.1 allowed to detect local and remote services when adding a new subscription in the calendar application.