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Azure Linux 3.0 Security Update: samba (CVE-2021-3738)

🗓️ 22 Jan 2026 00:00:00Reported by TenableType 
nessus
 nessus
🔗 www.tenable.com👁 5 Views

Samba on Azure Linux 3.0 vulnerable to CVE-2021-3738 enabling use-after-free and possible privilege escalation.

Related
Refs
Code
#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(296016);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/02/24");

  script_cve_id("CVE-2021-3738");
  script_xref(name:"IAVA", value:"2021-A-0554-S");

  script_name(english:"Azure Linux 3.0 Security Update: samba (CVE-2021-3738)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Azure Linux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The version of samba installed on the remote Azure Linux 3.0 host is prior to tested version. It is, therefore, affected
by a vulnerability as referenced in the CVE-2021-3738 advisory.

  - In DCE/RPC it is possible to share the handles (cookies for resource state) between multiple connections
    via a mechanism called 'association groups'. These handles can reference connections to our sam.ldb
    database. However while the database was correctly shared, the user credentials state was only pointed at,
    and when one connection within that association group ended, the database would be left pointing at an
    invalid 'struct session_info'. The most likely outcome here is a crash, but it is possible that the use-
    after-free could instead allow different user state to be pointed at and this might allow more privileged
    access. (CVE-2021-3738)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2021-3738");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-3738");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/11/09");
  script_set_attribute(attribute:"patch_publication_date", value:"2024/10/08");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/01/22");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:ctdb");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:libnetapi");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:libnetapi-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:libsmbclient");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:libsmbclient-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:libwbclient");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:libwbclient-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:python3-samba");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:python3-samba-test");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:samba");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:samba-client");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:samba-client-libs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:samba-common");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:samba-common-libs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:samba-common-tools");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:samba-dcerpc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:samba-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:samba-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:samba-krb5-printing");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:samba-libs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:samba-pidl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:samba-test");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:samba-test-libs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:samba-tools");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:samba-vfs-cephfs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:samba-vfs-glusterfs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:samba-winbind");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:samba-winbind-clients");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:samba-winbind-krb5-locator");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:microsoft:azure_linux:samba-winbind-modules");
  script_set_attribute(attribute:"cpe", value:"x-cpe:/o:microsoft:azure_linux");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Azure Linux Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info2.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/AzureLinux/release", "Host/AzureLinux/rpm-list", "Host/cpu");

  exit(0);
}
include('rpm.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var release = get_kb_item('Host/AzureLinux/release');
if (isnull(release) || 'Azure Linux' >!< release) audit(AUDIT_OS_NOT, 'Azure Linux');
var os_ver = pregmatch(pattern: "Azure Linux ([0-9]+(\.[0-9]+)?)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Azure Linux');
os_ver = os_ver[1];
if (! preg(pattern:"^3([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'Azure Linux 3.0', 'Azure Linux ' + os_ver);

if (!get_kb_item('Host/AzureLinux/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 'aarch64' >!< cpu)
  audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Azure Linux', cpu);

var pkgs = [
    {'reference':'ctdb-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'ctdb-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libnetapi-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libnetapi-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libnetapi-devel-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libnetapi-devel-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libsmbclient-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libsmbclient-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libsmbclient-devel-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libsmbclient-devel-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libwbclient-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libwbclient-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libwbclient-devel-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'libwbclient-devel-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'python3-samba-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'python3-samba-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'python3-samba-test-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'python3-samba-test-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-client-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-client-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-client-libs-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-client-libs-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-common-4.18.3-1.azl3', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-common-4.18.3-1.azl3', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-common-libs-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-common-libs-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-common-tools-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-common-tools-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-dcerpc-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-dcerpc-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-debuginfo-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-debuginfo-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-devel-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-devel-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-krb5-printing-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-krb5-printing-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-libs-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-libs-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-pidl-4.18.3-1.azl3', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-pidl-4.18.3-1.azl3', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-test-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-test-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-test-libs-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-test-libs-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-tools-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-tools-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-vfs-cephfs-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-vfs-cephfs-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-vfs-glusterfs-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-vfs-glusterfs-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-winbind-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-winbind-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-winbind-clients-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-winbind-clients-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-winbind-krb5-locator-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-winbind-krb5-locator-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-winbind-modules-4.18.3-1.azl3', 'cpu':'aarch64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'samba-winbind-modules-4.18.3-1.azl3', 'cpu':'x86_64', 'release':'3.0', 'rpm_spec_vers_cmp':TRUE}
];

var flag = 0;
foreach var package_array ( pkgs ) {
  var reference = NULL;
  var _release = NULL;
  var sp = NULL;
  var _cpu = NULL;
  var el_string = NULL;
  var rpm_spec_vers_cmp = NULL;
  var epoch = NULL;
  var allowmaj = NULL;
  var exists_check = NULL;
  var cves = NULL;
  if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
  if (!empty_or_null(package_array['release'])) _release = 'Azure Linux ' + package_array['release'];
  if (!empty_or_null(package_array['sp'])) sp = package_array['sp'];
  if (!empty_or_null(package_array['cpu'])) _cpu = package_array['cpu'];
  if (!empty_or_null(package_array['el_string'])) el_string = package_array['el_string'];
  if (!empty_or_null(package_array['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = package_array['rpm_spec_vers_cmp'];
  if (!empty_or_null(package_array['epoch'])) epoch = package_array['epoch'];
  if (!empty_or_null(package_array['allowmaj'])) allowmaj = package_array['allowmaj'];
  if (!empty_or_null(package_array['exists_check'])) exists_check = package_array['exists_check'];
  if (!empty_or_null(package_array['cves'])) cves = package_array['cves'];
  if (reference && _release && (!exists_check || rpm_exists(release:_release, rpm:exists_check))) {
    if (rpm_check(release:_release, sp:sp, cpu:_cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj, cves:cves)) flag++;
  }
}

if (flag)
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  var tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'ctdb / libnetapi / libnetapi-devel / libsmbclient / etc');
}

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24 Feb 2026 00:00Current
7.1High risk
Vulners AI Score7.1
CVSS 26.5
CVSS 3.18.8
EPSS0.01888
5