CentOS 9 : libxml2-2.9.13-18.el9

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The package checks in this plugin were extracted from
# the CentOS Stream Build Service.
##

include('compat.inc');

if (description)
{
  script_id(367947);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/20");

  script_cve_id(
    "CVE-2026-86138",
    "CVE-2026-86142",
    "CVE-2026-86143",
    "CVE-2026-86144"
  );
  script_xref(name:"IAVA", value:"2026-A-0980");

  script_name(english:"CentOS 9 : libxml2-2.9.13-18.el9");

  script_set_attribute(attribute:"synopsis", value:
"The remote CentOS host is missing one or more security updates for libxml2.");
  script_set_attribute(attribute:"description", value:
"The remote CentOS Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the
libxml2-2.9.13-18.el9 build changelog.

  - In xinclude in libxml2 before 2.15.4, xmlXIncludeProcess and xmlXIncludeProcessTree do not propagate
    parseFlags. This has security relevance for, for example, the XML_PARSE_NONET flag, if (without it) a
    custom resource loader accesses the internet and triggers XML external entity injection, SSRF, or a denial
    of service (e.g., for an attacker-controlled internet resource that is intentionally slow).
    (CVE-2026-86144)

  - In libxml2 before 2.15.4, xmlDictAddQString in dict.c has an integer overflow and resultant heap-based
    buffer overflow. (CVE-2026-86138)

  - In libxml2 before 2.15.4, there is a heap-based buffer overflow in xmlXPtrEvalXPtrPart because of
    xmlXPtrEval xpointer length saturation. (CVE-2026-86142)

  - In xmlIO in libxml2 before 2.15.4, an inconsistency in xmlOutputWriteCallback and xmlBufUse causes
    negative lengths to reach write callbacks, aka a lack of a check for integer overflow before calling
    writecallback. This has security relevance for many types of uses of that length value within a callback.
    (CVE-2026-86143)

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://kojihub.stream.centos.org/koji/buildinfo?buildID=132037");
  script_set_attribute(attribute:"solution", value:
"Update the CentOS 9 Stream libxml2 package.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:S/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/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-2026-86144");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/09/05");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/10/08");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/20");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:centos:centos:9");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:libxml2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:libxml2-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:libxml2-static");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:python3-libxml2");
  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:"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/local_checks_enabled", "Host/CentOS/release", "Host/CentOS/rpm-list", "Host/cpu");

  exit(0);
}


include('rpm2.inc');
include('rhel.inc');

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' >!< os_product) audit(AUDIT_OS_NOT, 'CentOS');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'CentOS');
if (!rhel_check_release(operator: 'ge', os_version: os_version, rhel_version: '9')) audit(AUDIT_OS_NOT, 'CentOS 9.x', 'CentOS ' + 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 ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 's390' >!< cpu && 'aarch64' >!< cpu && 'ppc' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'CentOS', cpu);

var constraints = [
  {
    'release': '9',
    'pkgs': [
      {'reference':'libxml2-2.9.13-18.el9', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libxml2-devel-2.9.13-18.el9', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libxml2-static-2.9.13-18.el9', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'python3-libxml2-2.9.13-18.el9', '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_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, 'libxml2 / libxml2-devel / libxml2-static / python3-libxml2');
}