CentOS Linux 7.9 [CIQ] Security Update: libxml2 / libxml2-debuginfo / libxml2-devel / libxml2-python / etc Multiple Vulnerabilities (ciqsa-2026_0708)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(353751);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/01");

  script_cve_id("CVE-2021-3516", "CVE-2021-3517", "CVE-2021-3518");

  script_name(english:"CentOS Linux 7.9 [CIQ] Security Update: libxml2 / libxml2-debuginfo / libxml2-devel / libxml2-python / etc Multiple Vulnerabilities (ciqsa-2026_0708)");

  script_set_attribute(attribute:"synopsis", value:
"The CentOS Linux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The CentOS Linux 7.9 host has packages installed that are affected by multiple vulnerabilities as referenced in the CIQ
ciqsa-2026_0708 advisory.

    This advisory aggregates security fixes for the libxml2 SRPM in CIQ CentOS Bridge 7.9. It addresses 3
    CVEs: CVE-2021-3516, CVE-2021-3517, CVE-2021-3518.

Tenable has extracted the preceding description block directly from the CIQ security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"https://github.com/ctrliq/advisories");
  # https://github.com/ctrliq/advisories/blob/main/csaf/vex/cve/2021/cve-2021-3516.json
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?ad0b659b");
  # https://github.com/ctrliq/advisories/blob/main/csaf/vex/cve/2021/cve-2021-3517.json
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?b34100fd");
  # https://github.com/ctrliq/advisories/blob/main/csaf/vex/cve/2021/cve-2021-3518.json
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?5b122ba8");
  # https://github.com/ctrliq/advisories/blob/main/csaf/advisories/ciq/2026/ciqsa-2026_0708.json
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?65c99257");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages based on the guidance in CIQ advisory ciqsa-2026_0708.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2021-3517");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2021-3518");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"vendor_severity", value:"High");

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/05/18");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/09/01");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/01");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"CentOS 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/OS/extended-third-party", "Host/local_checks_enabled", "Host/CentOS/release", "Host/CentOS/rpm-list", "Host/cpu");

  exit(0);
}
include('rpm2.inc');

var third_party_support = get_kb_item('Host/OS/extended-third-party');
if (empty_or_null(third_party_support) || third_party_support != 'CIQ') exit(0, 'CIQ support not enabled.');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_product = get_kb_item('installed_os/local/SSH/0/product');
if (isnull(os_product) || 'CentOS Linux' >!< os_product) audit(AUDIT_OS_NOT, 'CentOS Linux');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'CentOS Linux');
if (! preg(pattern:"^7.9([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'CentOS Linux 7.9', 'CentOS Linux ' + os_version);

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

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


var constraints = [
  {
    'release': '7',
    'sp': '9',
    'pkgs': [
      {'reference':'libxml2-2.9.1-6.1.el7_9.ciqcbr.6', 'sp':'9', 'cpu':'i686', 'el_string':'el7_9', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'libxml2-2.9.1-6.1.el7_9.ciqcbr.6', 'sp':'9', 'cpu':'x86_64', 'el_string':'el7_9', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'libxml2-debuginfo-2.9.1-6.1.el7_9.ciqcbr.6', 'sp':'9', 'cpu':'i686', 'el_string':'el7_9', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'libxml2-debuginfo-2.9.1-6.1.el7_9.ciqcbr.6', 'sp':'9', 'cpu':'x86_64', 'el_string':'el7_9', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'libxml2-devel-2.9.1-6.1.el7_9.ciqcbr.6', 'sp':'9', 'cpu':'i686', 'el_string':'el7_9', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'libxml2-devel-2.9.1-6.1.el7_9.ciqcbr.6', 'sp':'9', 'cpu':'x86_64', 'el_string':'el7_9', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'libxml2-python-2.9.1-6.1.el7_9.ciqcbr.6', 'sp':'9', 'cpu':'i686', 'el_string':'el7_9', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'libxml2-python-2.9.1-6.1.el7_9.ciqcbr.6', 'sp':'9', 'cpu':'x86_64', 'el_string':'el7_9', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'libxml2-static-2.9.1-6.1.el7_9.ciqcbr.6', 'sp':'9', 'cpu':'i686', 'el_string':'el7_9', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'libxml2-static-2.9.1-6.1.el7_9.ciqcbr.6', 'sp':'9', 'cpu':'x86_64', 'el_string':'el7_9', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'}
    ]
  }
];

var os_release = get_one_kb_item('installed_os/local/SSH/0/release');
var os_sp = get_one_kb_item('Host/*/minor_release');

var flag = 0;
var reference;
var sp;
var _cpu;
var el_string;
var rpm_spec_vers_cmp;
var epoch;
var allowmaj;
var exists_check;
var cves;
foreach var constraint ( constraints ) {
  # Check that the target release is equal to the affected release
  if (!empty_or_null(constraint['release'])){
    if (constraint['release'] != os_release) continue;
  }
  if (!empty_or_null(constraint['sp'])){
    if (constraint['sp'] != os_sp) continue;
  }
  foreach var pkg ( constraint['pkgs'] ) {
    reference = NULL;
    sp = NULL;
    _cpu = NULL;
    el_string = NULL;
    rpm_spec_vers_cmp = NULL;
    epoch = NULL;
    allowmaj = NULL;
    exists_check = NULL;
    cves = NULL;
    if (!empty_or_null(pkg['reference'])) reference = pkg['reference'];
    if (!empty_or_null(pkg['sp'])) sp = pkg['sp'];
    if (!empty_or_null(pkg['cpu'])) _cpu = pkg['cpu'];
    if (!empty_or_null(pkg['el_string'])) el_string = pkg['el_string'];
    if (!empty_or_null(pkg['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = pkg['rpm_spec_vers_cmp'];
    if (!empty_or_null(pkg['epoch'])) epoch = pkg['epoch'];
    if (!empty_or_null(pkg['allowmaj'])) allowmaj = pkg['allowmaj'];
    if (!empty_or_null(pkg['exists_check'])) exists_check = pkg['exists_check'];
    if (!empty_or_null(pkg['cves'])) cves = pkg['cves'];
    if (reference &&
        ## (no known rpm to check OR known rpm_exists)
        (!exists_check || rpm_exists(rpm:exists_check)) &&
        rpm_check(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_HOLE,
      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, 'libxml2 / libxml2-debuginfo / libxml2-devel / libxml2-python / etc');
}