Nextcloud also ships a CLI utility called nextcloudcmd which is sometimes used for automated scripting and headless servers. Versions of nextcloudcmd prior to 3.6.1 would incorrectly trust invalid TLS certificates, which may enable a Man-in-the-middle attack that exposes sensitive data or credentials to a network attacker. This affects the CLI only. It does not affect the standard GUI desktop Nextcloud clients, and it does not affect the Nextcloud server.
https://hackerone.com/reports/1699740
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-82xx-98xv-4jxv