DISPUTED systemd 239 through 245 accepts any certificate signed by a trusted certificate authority for DNS Over TLS. Server Name Indication (SNI) is not sent, and there is no hostname validation with the GnuTLS backend. NOTE: This has been disputed by the developer as not a vulnerability since hostname validation does not have anything to do with this issue (i.e. there is no hostname to be sent).
blog.cloudflare.com/dns-encryption-explained/
github.com/systemd/systemd/blob/v239/man/resolved.conf.xml
github.com/systemd/systemd/blob/v243/man/resolved.conf.xml
github.com/systemd/systemd/blob/v243/src/resolve/resolved-dnstls-gnutls.c
github.com/systemd/systemd/issues/9397
github.com/systemd/systemd/pull/13870
lists.fedoraproject.org/archives/list/[email protected]/message/4NLJVOJMB6ANDILRLDZK26YGLYBEPHKY/
security.netapp.com/advisory/ntap-20191122-0002/
tools.ietf.org/html/rfc7858