CentOS Linux 7 [TuxCare] Security Update: libxml2 / libxml2-devel / libxml2-python / libxml2-static Multiple Vulnerabilities (CENTOS7:CLSA-2023:1696537106)

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

include('compat.inc');

if (description)
{
  script_id(362120);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/01");

  script_cve_id(
    "CVE-2021-3517",
    "CVE-2021-3518",
    "CVE-2022-23308",
    "CVE-2022-40303",
    "CVE-2022-40304"
  );
  script_xref(name:"CLSA", value:"2023:1696537106");

  script_name(english:"CentOS Linux 7 [TuxCare] Security Update: libxml2 / libxml2-devel / libxml2-python / libxml2-static Multiple Vulnerabilities (CENTOS7:CLSA-2023:1696537106)");

  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 host has packages installed that are affected by multiple vulnerabilities as referenced in the
TuxCare CENTOS7:CLSA-2023:1696537106 advisory.

  - There is a flaw in the xml entity encoding functionality of libxml2 in versions before 2.9.11. An attacker
    who is able to supply a crafted file to be processed by an application linked with the affected
    functionality of libxml2 could trigger an out-of-bounds read. The most likely impact of this flaw is to
    application availability, with some potential impact to confidentiality and integrity if an attacker is
    able to use memory information to further exploit the application. (CVE-2021-3517)

  - There's a flaw in libxml2 in versions before 2.9.11. An attacker who is able to submit a crafted file to
    be processed by an application linked with libxml2 could trigger a use-after-free. The greatest impact
    from this flaw is to confidentiality, integrity, and availability. (CVE-2021-3518)

  - valid.c in libxml2 before 2.9.13 has a use-after-free of ID and IDREF attributes. (CVE-2022-23308)

  - An issue was discovered in libxml2 before 2.10.3. When parsing a multi-gigabyte XML document with the
    XML_PARSE_HUGE parser option enabled, several integer counters can overflow. This results in an attempt to
    access an array at a negative 2GB offset, typically leading to a segmentation fault. (CVE-2022-40303)

  - An issue was discovered in libxml2 before 2.10.3. Certain invalid XML entity definitions can corrupt a
    hash table key, potentially leading to subsequent logic errors. In one case, a double-free can be
    provoked. (CVE-2022-40304)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
  # https://security.tuxcare.com/csaf/v2/els_os/centos7els/advisories/2023/clsa-2023_1696537106.json
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?dc85f1ed");
  script_set_attribute(attribute:"see_also", value:"https://cve.tuxcare.com/els/releases/CLSA-2023:1696537106");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages based on the guidance in TuxCare advisory CENTOS7:CLSA-2023:1696537106.");
  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:"Important");

  script_set_attribute(attribute:"vuln_publication_date", value:"2021/05/18");
  script_set_attribute(attribute:"patch_publication_date", value:"2023/10/05");
  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");

  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 != 'TuxCare') exit(0, 'TuxCare 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([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'CentOS Linux 7', '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',
    'pkgs': [
      {'reference':'libxml2-2.9.1-6.el7_9.6.tuxcare.els1', 'cpu':'i686', 'el_string':'el7_9', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libxml2-2.9.1-6.el7_9.6.tuxcare.els1', 'cpu':'x86_64', 'el_string':'el7_9', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libxml2-devel-2.9.1-6.el7_9.6.tuxcare.els1', 'cpu':'i686', 'el_string':'el7_9', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libxml2-devel-2.9.1-6.el7_9.6.tuxcare.els1', 'cpu':'x86_64', 'el_string':'el7_9', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libxml2-python-2.9.1-6.el7_9.6.tuxcare.els1', 'cpu':'x86_64', 'el_string':'el7_9', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libxml2-static-2.9.1-6.el7_9.6.tuxcare.els1', 'cpu':'i686', 'el_string':'el7_9', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libxml2-static-2.9.1-6.el7_9.6.tuxcare.els1', 'cpu':'x86_64', 'el_string':'el7_9', 'rpm_spec_vers_cmp':TRUE}
    ]
  }
];

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-devel / libxml2-python / libxml2-static');
}