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Fencer Vulns
medium 6.5

CVE-2018-16851 json

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.

published 2018-11-28 7 y ago modified 2026-06-17 4 mo ago also EUVD-2018-8645

cvss
6.5
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
3.3%
EPSS 3.3% chance of exploitation in 30 days, percentile 88%
public exploits
0
none known

Summary

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.

Patch / fix

  • samba samba 4.7.12, 4.8.7, 4.9.3
  • samba Debian 14, Debian 13, Debian 12 2:4.9.2+dfsg-2

debian advisories DEBIAN-CVE-2018-16851

  • samba Ubuntu 14.04 LTS 2:4.3.11+dfsg-0ubuntu0.14.04.19
  • samba Ubuntu 16.04 LTS 2:4.3.11+dfsg-0ubuntu0.16.04.18
  • samba Ubuntu 18.04 LTS 2:4.7.6+dfsg~ubuntu-0ubuntu2.5

ubuntu advisories UBUNTU-CVE-2018-16851

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • samba SLE Module for Package Hub 15, SLE Module for Basesystem 15, SLE High Availability Extension 15 4.7.11+git.140.6bd0e5b30d8-4.21.1

suse advisories SUSE-SU-2018:4066-1

  • samba openSUSE Tumbleweed 4.14.6+git.182.2205d5224e3-1.1

opensuse advisories openSUSE-SU-2024:11365-1

  • samba Alpine 3.24, Alpine 3.23, Alpine 3.22 +13 more 4.8.7-r0
  • samba Alpine 3.6 4.6.16-r2
  • samba Alpine 3.7 4.7.6-r2
  • samba Alpine 3.8 4.8.8-r0

alpine advisories ALPINE-CVE-2018-16851

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • samba Arch Linux 4.9.3-1

arch linux advisories AVG-823

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2018-16851 updated cvss 6.5

samba: NULL pointer de-reference in Samba AD DC LDAP server

  • Red Hat Enterprise Linux 5 samba Red Hat Enterprise Linux 6 samba4, samba4-dc, samba4-libs, samba4-pidl, samba4-swat, samba4-test, +7 more Red Hat Enterprise Linux 7 ctdb, samba, samba-dc, ctdb-tests, samba-libs, samba-pidl, +18 more Red Hat Enterprise Linux 8 ctdb, samba, libnetapi, ctdb-tests, samba-libs, samba-pidl, +24 more Red Hat Storage 3 ctdb, samba, samba-dc, ctdb-tests, samba-libs, samba-pidl, +21 more Red Hat Virtualization 4 samba
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

3.25% chance of exploitation in the next 30 days, higher than 88% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.0 6.5 CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 4.0 AV:N/AC:L/Au:S/C:N/I:N/A:P

Affected products

  • [UNKNOWN] samba

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.