Weechat -- Possible man-in-the-middle attack in TLS connection to servers

The Weechat project reports:

After changing the options weechat.network.gnutls_ca_system or weechat.network.gnutls_ca_user, the TLS verification function is lost. Consequently, any connection to a server with TLS is made without verifying the certificate, which could lead to a man-in-the-middle attack. Connection to IRC servers with TLS is affected, as well as any connection a server made by a plugin or a script using the function hook_connect.

[source]