The cyrus-imapd packages contain a high-performance mail server with IMAP, POP3, NNTP, and Sieve support. An authentication bypass flaw was found in the cyrus-imapd NNTP server, nntpd. A remote user able to use the nntpd service could use this flaw to read or post newsgroup messages on an NNTP server configured to require user authentication, without providing valid authentication credentials. A ...