AlmaLinux 9.2 [TuxCare] Security Update: libxml2 / libxml2-devel / libxml2-static / python3-libxml2 Multiple Vulnerabilities (ALMALINUX9.2:CLSA-2026:1775649722)

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

include('compat.inc');

if (description)
{
  script_id(361098);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/01");

  script_cve_id(
    "CVE-2024-34459",
    "CVE-2025-8732",
    "CVE-2026-0989",
    "CVE-2026-0990",
    "CVE-2026-0992",
    "CVE-2026-1757"
  );
  script_xref(name:"CLSA", value:"2026:1775649722");

  script_name(english:"AlmaLinux 9.2 [TuxCare] Security Update: libxml2 / libxml2-devel / libxml2-static / python3-libxml2 Multiple Vulnerabilities (ALMALINUX9.2:CLSA-2026:1775649722)");

  script_set_attribute(attribute:"synopsis", value:
"The AlmaLinux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The AlmaLinux 9.2 host has packages installed that are affected by multiple vulnerabilities as referenced in the TuxCare
ALMALINUX9.2:CLSA-2026:1775649722 advisory.

  - An issue was discovered in xmllint (from libxml2) before 2.11.8 and 2.12.x before 2.12.7. Formatting error
    messages with xmllint --htmlout can result in a buffer over-read in xmlHTMLPrintFileContext in xmllint.c.
    (CVE-2024-34459)

  - A vulnerability was found in libxml2 up to 2.14.5. It has been declared as problematic. This vulnerability
    affects the function xmlParseSGMLCatalog of the component xmlcatalog. The manipulation leads to
    uncontrolled recursion. Attacking locally is a requirement. The exploit has been disclosed to the public
    and may be used. The real existence of this vulnerability is still doubted at the moment. The code
    maintainer explains, that [t]he issue can only be triggered with untrusted SGML catalogs and it makes
    absolutely no sense to use untrusted catalogs. I also doubt that anyone is still using SGML catalogs at
    all. (CVE-2025-8732)

  - A flaw was identified in the RelaxNG parser of libxml2 related to how external schema inclusions are
    handled. The parser does not enforce a limit on inclusion depth when resolving nested <include>
    directives. Specially crafted or overly complex schemas can cause excessive recursion during parsing. This
    may lead to stack exhaustion and application crashes, creating a denial-of-service risk. (CVE-2026-0989)

  - A flaw was found in libxml2, an XML parsing library. This uncontrolled recursion vulnerability occurs in
    the xmlCatalogXMLResolveURI function when an XML catalog contains a delegate URI entry that references
    itself. A remote attacker could exploit this configuration-dependent issue by providing a specially
    crafted XML catalog, leading to infinite recursion and call stack exhaustion. This ultimately results in a
    segmentation fault, causing a Denial of Service (DoS) by crashing affected applications. (CVE-2026-0990)

  - A flaw was found in the libxml2 library. This uncontrolled resource consumption vulnerability occurs when
    processing XML catalogs that contain repeated <nextCatalog> elements pointing to the same downstream
    catalog. A remote attacker can exploit this by supplying crafted catalogs, causing the parser to
    redundantly traverse catalog chains. This leads to excessive CPU consumption and degrades application
    availability, resulting in a denial-of-service condition. (CVE-2026-0992)

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/almalinux9.2esu/advisories/2026/clsa-2026_1775649722.json
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?88be48c5");
  script_set_attribute(attribute:"see_also", value:"https://cve.tuxcare.com/els/releases/CLSA-2026:1775649722");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages based on the guidance in TuxCare advisory ALMALINUX9.2:CLSA-2026:1775649722.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:S/C:N/I:N/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:N/S:U/C:H/I:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss4_vector", value:"CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:P");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2025-8732");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2024-34459");

  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:"Moderate");

  script_set_attribute(attribute:"vuln_publication_date", value:"2023/12/12");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/04/08");
  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:"Alma 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/OS/extended-third-party", "Host/local_checks_enabled", "Host/AlmaLinux/release", "Host/AlmaLinux/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 != '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) || 'AlmaLinux' >!< os_product) audit(AUDIT_OS_NOT, 'AlmaLinux');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'AlmaLinux');
if (! preg(pattern:"^9.2([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'AlmaLinux 9.2', 'AlmaLinux ' + os_version);

if (!get_kb_item('Host/AlmaLinux/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, 'AlmaLinux', cpu);


var constraints = [
  {
    'release': '9',
    'sp': '2',
    'pkgs': [
      {'reference':'libxml2-2.9.13-3.el9_2.1.tuxcare.els12', 'sp':'2', 'cpu':'i686', 'el_string':'el9_2', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libxml2-2.9.13-3.el9_2.1.tuxcare.els12', 'sp':'2', 'cpu':'x86_64', 'el_string':'el9_2', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libxml2-devel-2.9.13-3.el9_2.1.tuxcare.els12', 'sp':'2', 'cpu':'i686', 'el_string':'el9_2', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libxml2-devel-2.9.13-3.el9_2.1.tuxcare.els12', 'sp':'2', 'cpu':'x86_64', 'el_string':'el9_2', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'libxml2-static-2.9.13-3.el9_2.1.tuxcare.els12', 'sp':'2', 'cpu':'x86_64', 'el_string':'el9_2', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'python3-libxml2-2.9.13-3.el9_2.1.tuxcare.els12', 'sp':'2', 'cpu':'x86_64', 'el_string':'el9_2', '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_NOTE,
      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');
}