This indicates an attack attempt to exploit an Information Disclosure vulnerability in Samba.
The vulnerability is caused by an error when the vulnerable software handles a specially crafted SMB request. A remote attacker may be able to exploit this to disclose memory information on the targeted system.
Samba Team Samba 3.6.0 to 4.5.14
Samba Team Samba 3.6.0 to 4.6.10
Samba Team Samba 3.6.0 to 4.7.2
Information Disclosure: Remote attackers can gain sensitive information from vulnerable systems
Apply the most recent upgrade or patch from the vendor.