net-snmp provides various tools relating to the Simple Network Management Protocol. Prior to version 5.9.2, a user with read-only credentials can use a malformed OID in a GET-NEXT to the nsVacmAccessTable to cause a NULL pointer dereference. Version 5.9.2 contains a patch. Users should use strong SNMPv3 credentials and avoid sharing the credentials. Those who must use SNMPv1 or SNMPv2c should use a complex community string and enhance the protection by restricting access to a given IP address range.
A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.