Add entry about recent Samba4* vulnerabilities:

CVE-2020-27840: An anonymous attacker can crash the Samba AD DC LDAP server by sending easily crafted DNs as part of a bind request. More serious heap corruption is likely also possible.
CVE-2021-20277: User-controlled LDAP filter strings against the AD DC LDAP server may crash the LDAP server.

Security: CVE-2020-27840

		CVE-2021-20277