This indicates an attack attempt to exploit a Memory Corruption Vulnerability in Samba libsmbclient library.
The vulnerability is due to an error in the vulnerable application when handling a maliciously crafted request. A remote attacker may be able to exploit this to execute arbitrary codes or cause a denial of service condition on the affected system.
Samba 3.2.0 - 4.8.3 (inclusive)
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor: