CVE-2018-16851: Null Pointer Dereference
Last updated 25 August 2025
Other sources
Samba from version 4.0.0 and before versions 4.7.12, 4.8.7, 4.9.3 is vulnerable to a denial of service. During the processing of an LDAP search before Samba's AD DC returns the LDAP entries to the client, the entries are cached in a single memory object with a maximum size of 256MB. When this size is reached, the Samba process providing the LDAP service will follow the NULL pointer, terminating the process. There is no further vulnerability associated with this issue, merely a denial of service.
— Launchpad
Affected Software
Remediation
Patch Available
Event History
Frequently Asked Questions
What is the severity of CVE-2018-16851?
CVE-2018-16851 is classified as a denial of service vulnerability affecting Samba.
How do I fix CVE-2018-16851?
To fix CVE-2018-16851, upgrade Samba to version 4.7.12, 4.8.7, or 4.9.3 or later.
Which versions of Samba are affected by CVE-2018-16851?
Samba versions from 4.0.0 up to, but not including, 4.7.12, 4.8.7, and 4.9.3 are affected by CVE-2018-16851.
Is Ubuntu impacted by CVE-2018-16851?
Yes, certain versions of Ubuntu with Samba versions prior to 4.7.12, 4.8.7, and 4.9.3 are impacted by CVE-2018-16851.
How can I identify if my system is vulnerable to CVE-2018-16851?
You can identify vulnerability to CVE-2018-16851 by checking your Samba version against the affected versions listed in the CVE description.