GNOME Balsa any version

In GNOME Balsa before 2.6.0, a malicious server operator or man in the middle can trigger a NULL pointer dereference and client crash by sending a PREAUTH response to imap_mbox_connect in libbalsa/imap/imap-handle.c.

In GNOME glib-networking through 2.64.2, the implementation of GTlsClientConnection skips hostname verification of the server's TLS certificate if the application fails to specify the expected server identity. This is in contrast to its intended documented behavior, to fail the certificate verification. Applications that fail to provide the server identity, including Balsa before 2.5.11 and 2.6.x before 2.6.1, accept a TLS certificate if the certificate is valid for any host.