Vulnerability Monitor

The vendors, products, and vulnerabilities you care about

CVE-2018-16851

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.

Security Impact Summary

This vulnerability carries a MEDIUM severity rating with a CVSS v3.1 score of 6.5, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction requiring only low-level privileges . The vulnerability impacts and availability (service disruption) for affected systems. Impacting 3 products from samba, from canonical, from debian organizations running these solutions should prioritize assessment and patching.

Historical Context

First disclosed in 2018, this vulnerability was reported during a period defined by widespread IoT adoption challenges, mobile security concerns, and the emergence of advanced persistent threat (APT) techniques. Contemporary mitigation strategies focused on secure development practices and third-party component vetting.

Published

2018-11-28T14:29:00.423

Last Modified

2026-06-17T01:44:54.590

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 6.5 (MEDIUM)

CVSSv2 Vector

AV:N/AC:L/Au:S/C:N/I:N/A:P

Access Vector: NETWORK
Access Complexity: LOW
Authentication: SINGLE
Confidentiality Impact: NONE
Integrity Impact: NONE
Availability Impact: PARTIAL

Exploitability Score

8.0

Impact Score

2.9

Weaknesses

Type: Secondary
CWE-476
Type: Primary
CWE-476

Affected Vendors & Products

Type	Vendor	Product	Version/Range	Vulnerable?
Application	samba	samba	< 4.7.12	Yes
Application	samba	samba	< 4.8.7	Yes
Application	samba	samba	< 4.9.3	Yes
Operating System	canonical	ubuntu_linux	12.04	Yes
Operating System	canonical	ubuntu_linux	14.04	Yes
Operating System	canonical	ubuntu_linux	16.04	Yes
Operating System	canonical	ubuntu_linux	18.04	Yes
Operating System	canonical	ubuntu_linux	18.10	Yes
Operating System	debian	debian_linux	8.0	Yes
Operating System	debian	debian_linux	9.0	Yes

References

http://www.securityfocus.com/bid/106027 Third Party Advisory, VDB Entry ([email protected])
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16851 Issue Tracking, Third Party Advisory ([email protected])
https://lists.debian.org/debian-lts-announce/2018/12/msg00005.html Mailing List, Third Party Advisory ([email protected])
https://security.gentoo.org/glsa/202003-52 Third Party Advisory ([email protected])
https://security.netapp.com/advisory/ntap-20181127-0001/ Third Party Advisory ([email protected])
https://usn.ubuntu.com/3827-1/ Third Party Advisory ([email protected])
https://usn.ubuntu.com/3827-2/ Third Party Advisory ([email protected])
https://www.debian.org/security/2018/dsa-4345 Third Party Advisory ([email protected])
https://www.samba.org/samba/security/CVE-2018-16851.html Patch, Vendor Advisory ([email protected])
http://www.securityfocus.com/bid/106027 Third Party Advisory, VDB Entry (af854a3a-2127-422b-91ae-364da2661108)
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16851 Issue Tracking, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://lists.debian.org/debian-lts-announce/2018/12/msg00005.html Mailing List, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://security.gentoo.org/glsa/202003-52 Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://security.netapp.com/advisory/ntap-20181127-0001/ Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://usn.ubuntu.com/3827-1/ Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://usn.ubuntu.com/3827-2/ Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://www.debian.org/security/2018/dsa-4345 Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://www.samba.org/samba/security/CVE-2018-16851.html Patch, Vendor Advisory (af854a3a-2127-422b-91ae-364da2661108)

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For samba's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.