Ubuntu 25.10 / 26.04 LTS : libxml2 vulnerabilities (USN-8460-1)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-8460-1. The text
# itself is copyright (C) Canonical, Inc. See
# <https://ubuntu.com/security/notices>. Ubuntu(R) is a registered
# trademark of Canonical, Inc.
##

include('compat.inc');

if (description)
{
  script_id(322260);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/06/23");

  script_cve_id("CVE-2026-1757", "CVE-2026-6732");
  script_xref(name:"USN", value:"8460-1");

  script_name(english:"Ubuntu 25.10 / 26.04 LTS : libxml2 vulnerabilities (USN-8460-1)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Ubuntu host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Ubuntu 25.10 / 26.04 LTS host has packages installed that are affected by multiple vulnerabilities as
referenced in the USN-8460-1 advisory.

    It was discovered that libxml2 did not properly release memory allocated in the xmllint utility. An
    attacker could possibly use this issue to cause a denial of service. (CVE-2026-1757)

    A type confusion vulnerability was found in libxml2 when processing a specially crafted XML document. A
    remote attacker could possibly use this issue to cause a denial of service. (CVE-2026-6732)

Tenable has extracted the preceding description block directly from the Ubuntu 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://ubuntu.com/security/notices/USN-8460-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C");
  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:N/I:N/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-2026-6732");

  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:"2026/02/02");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/06/22");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/06/23");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:25.10");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:26.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libxml2-16");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libxml2-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libxml2-source");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libxml2-utils");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:python3-libxml2");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

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

  script_copyright(english:"Ubuntu Security Notice (C) 2026 Canonical, Inc. / NASL script (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");

  exit(0);
}

include('debian_package.inc');

if ( ! get_kb_item('Host/local_checks_enabled') ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_release = get_kb_item('Host/Ubuntu/release');
if ( isnull(os_release) ) audit(AUDIT_OS_NOT, 'Ubuntu');
os_release = chomp(os_release);
if (! ('25.10' >< os_release || '26.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 25.10 / 26.04', 'Ubuntu ' + os_release);
if ( ! get_kb_item('Host/Debian/dpkg-l') ) 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) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Ubuntu', cpu);

var pkgs = [
    {'osver': '25.10', 'pkgname': 'libxml2-16', 'pkgver': '2.14.5+dfsg-0.2ubuntu0.2'},
    {'osver': '25.10', 'pkgname': 'libxml2-dev', 'pkgver': '2.14.5+dfsg-0.2ubuntu0.2'},
    {'osver': '25.10', 'pkgname': 'libxml2-utils', 'pkgver': '2.14.5+dfsg-0.2ubuntu0.2'},
    {'osver': '25.10', 'pkgname': 'python3-libxml2', 'pkgver': '2.14.5+dfsg-0.2ubuntu0.2'},
    {'osver': '26.04', 'pkgname': 'libxml2-16', 'pkgver': '2.15.2+dfsg-0.1ubuntu0.1'},
    {'osver': '26.04', 'pkgname': 'libxml2-dev', 'pkgver': '2.15.2+dfsg-0.1ubuntu0.1'},
    {'osver': '26.04', 'pkgname': 'libxml2-source', 'pkgver': '2.15.2+dfsg-0.1ubuntu0.1'},
    {'osver': '26.04', 'pkgname': 'libxml2-utils', 'pkgver': '2.15.2+dfsg-0.1ubuntu0.1'},
    {'osver': '26.04', 'pkgname': 'python3-libxml2', 'pkgver': '2.15.2+dfsg-0.1ubuntu0.1'}
];

var flag = 0;
foreach var package_array ( pkgs ) {
  var osver = NULL;
  var pkgname = NULL;
  var pkgver = NULL;
  if (!empty_or_null(package_array['osver'])) osver = package_array['osver'];
  if (!empty_or_null(package_array['pkgname'])) pkgname = package_array['pkgname'];
  if (!empty_or_null(package_array['pkgver'])) pkgver = package_array['pkgver'];
  if (!empty_or_null(package_array['cves'])) cves = package_array['cves'];
  if (osver && pkgname && pkgver) {
    if (deb_check(release:osver, prefix:pkgname, reference:pkgver, cves:cves)) flag++;
  }
}

if (flag)
{
  var extra = '';
  extra += ubuntu_report_get();
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : extra
  );
  exit(0);
}
else
{
  var tested = ubuntu_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'libxml2-16 / libxml2-dev / libxml2-source / libxml2-utils / etc');
}