The remote Debian host is missing a security-related update.
Several vulnerabilities have been discovered in Samba, a SMB/CIFS file, print, and login server for Unix. The Common Vulnerabilities and Exposures project identifies the following issues : - CVE-2018-14629 Florian Stuelpner discovered that Samba is vulnerable to infinite query recursion caused by CNAME loops, resulting in denial of service. https://www.samba.org/samba/security/CVE-2018-14629.html - CVE-2018-16841 Alex MacCuish discovered that a user with a valid certificate or smart card can crash the Samba AD DC's KDC when configured to accept smart-card authentication. https://www.samba.org/samba/security/CVE-2018-16841.html - CVE-2018-16851 Garming Sam of the Samba Team and Catalyst discovered a NULL pointer dereference vulnerability in the Samba AD DC LDAP server allowing a user able to read more than 256MB of LDAP entries to crash the Samba AD DC's LDAP server. https://www.samba.org/samba/security/CVE-2018-16851.html
Upgrade the samba packages. For the stable distribution (stretch), these problems have been fixed in version 2:4.5.12+dfsg-2+deb9u4.