Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS : Expat vulnerabilities (USN-8790-1)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-8790-1. 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(350305);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/25");

  script_cve_id(
    "CVE-2025-59375",
    "CVE-2026-32776",
    "CVE-2026-32777",
    "CVE-2026-32778",
    "CVE-2026-41080",
    "CVE-2026-45186",
    "CVE-2026-50219",
    "CVE-2026-56403",
    "CVE-2026-56404",
    "CVE-2026-56405",
    "CVE-2026-56408",
    "CVE-2026-56412"
  );
  script_xref(name:"IAVA", value:"2026-A-0407-S");
  script_xref(name:"IAVA", value:"2026-A-0451");
  script_xref(name:"IAVA", value:"2026-A-0650-S");
  script_xref(name:"USN", value:"8790-1");

  script_name(english:"Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS : Expat vulnerabilities (USN-8790-1)");

  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 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS host has packages
installed that are affected by multiple vulnerabilities as referenced in the USN-8790-1 advisory.

    It was discovered that Expat could be made to allocate large amounts of memory when parsing a small
    crafted document. An attacker could possibly use this issue to cause Expat to consume resources, leading
    to a denial of service. This issue was only addressed in Ubuntu 24.04 LTS. (CVE-2025-59375)

    It was discovered that Expat incorrectly handled empty external parameter entity content. An attacker
    could possibly use this issue to cause Expat to crash, resulting in a denial of service. (CVE-2026-32776)

    It was discovered that Expat incorrectly handled certain DTD content. An attacker could possibly use this
    issue to cause Expat to enter an infinite loop, resulting in a denial of service. (CVE-2026-32777)

    It was discovered that Expat incorrectly handled memory when retrying after an earlier out-of-memory
    condition. An attacker could possibly use this issue to cause Expat to crash, resulting in a denial of
    service. (CVE-2026-32778)

    It was discovered that Expat performed attribute name collision checks inefficiently. An attacker could
    possibly use this issue to cause Expat to consume resources when processing a moderately sized crafted XML
    document, resulting in a denial of service.

    This issue was only addressed in Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-45186)

    It was discovered that Expat used insufficient entropy, allowing hash flooding through a crafted XML
    document. An attacker could possibly use this issue to cause Expat to consume resources, leading to a
    denial of service.

    This issue was only addressed in Ubuntu 14.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS.
    (CVE-2026-41080)

    It was discovered that Expat did not track handler call depth for certain functions called from within
    handlers, leading to a use-after-free. An attacker could possibly use this issue to cause Expat to crash,
    resulting in a denial of service, or possibly execute arbitrary code. (CVE-2026-50219, CVE-2026-56412)

    It was discovered that Expat incorrectly handled certain values, leading to integer overflows. An attacker
    could possibly use this issue to cause Expat to crash, resulting in a denial of service. (CVE-2026-56403,
    CVE-2026-56404, CVE-2026-56405)

    It was discovered that Expat incorrectly handled certain values, leading to an integer overflow. An
    attacker could possibly use this issue to cause Expat to crash, resulting in a denial of service. This
    issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu
    26.04 LTS. (CVE-2026-56408)

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-8790-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected expat, lib64expat1 and / or libexpat1 packages.");
  script_set_cvss_base_vector("CVSS2#AV:L/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:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-56412");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2026-56405");

  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:"2026/03/16");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/09/21");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/25");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:14.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:20.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:22.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:24.04:-:lts");
  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:expat");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:lib64expat1");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libexpat1");
  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:"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 (! ('14.04' >< os_release || '16.04' >< os_release || '18.04' >< os_release || '20.04' >< os_release || '22.04' >< os_release || '24.04' >< os_release || '26.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 14.04 / 16.04 / 18.04 / 20.04 / 22.04 / 24.04 / 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': '14.04', 'pkgname': 'expat', 'pkgver': '2.1.0-4ubuntu1.4+esm12', 'cves': ['CVE-2025-59375', 'CVE-2026-32776', 'CVE-2026-32777', 'CVE-2026-32778', 'CVE-2026-41080', 'CVE-2026-45186', 'CVE-2026-50219', 'CVE-2026-56403', 'CVE-2026-56404', 'CVE-2026-56405', 'CVE-2026-56412']},
    {'osver': '14.04', 'pkgname': 'lib64expat1', 'pkgver': '2.1.0-4ubuntu1.4+esm12', 'cves': ['CVE-2025-59375', 'CVE-2026-32776', 'CVE-2026-32777', 'CVE-2026-32778', 'CVE-2026-41080', 'CVE-2026-45186', 'CVE-2026-50219', 'CVE-2026-56403', 'CVE-2026-56404', 'CVE-2026-56405', 'CVE-2026-56412']},
    {'osver': '14.04', 'pkgname': 'libexpat1', 'pkgver': '2.1.0-4ubuntu1.4+esm12', 'cves': ['CVE-2025-59375', 'CVE-2026-32776', 'CVE-2026-32777', 'CVE-2026-32778', 'CVE-2026-41080', 'CVE-2026-45186', 'CVE-2026-50219', 'CVE-2026-56403', 'CVE-2026-56404', 'CVE-2026-56405', 'CVE-2026-56412']},
    {'osver': '16.04', 'pkgname': 'expat', 'pkgver': '2.1.0-7ubuntu0.16.04.5+esm13', 'cves': ['CVE-2025-59375', 'CVE-2026-32776', 'CVE-2026-32777', 'CVE-2026-32778', 'CVE-2026-41080', 'CVE-2026-45186', 'CVE-2026-50219', 'CVE-2026-56403', 'CVE-2026-56404', 'CVE-2026-56405', 'CVE-2026-56412']},
    {'osver': '16.04', 'pkgname': 'lib64expat1', 'pkgver': '2.1.0-7ubuntu0.16.04.5+esm13', 'cves': ['CVE-2025-59375', 'CVE-2026-32776', 'CVE-2026-32777', 'CVE-2026-32778', 'CVE-2026-41080', 'CVE-2026-45186', 'CVE-2026-50219', 'CVE-2026-56403', 'CVE-2026-56404', 'CVE-2026-56405', 'CVE-2026-56412']},
    {'osver': '16.04', 'pkgname': 'libexpat1', 'pkgver': '2.1.0-7ubuntu0.16.04.5+esm13', 'cves': ['CVE-2025-59375', 'CVE-2026-32776', 'CVE-2026-32777', 'CVE-2026-32778', 'CVE-2026-41080', 'CVE-2026-45186', 'CVE-2026-50219', 'CVE-2026-56403', 'CVE-2026-56404', 'CVE-2026-56405', 'CVE-2026-56412']},
    {'osver': '18.04', 'pkgname': 'expat', 'pkgver': '2.2.5-3ubuntu0.9+esm4', 'cves': ['CVE-2025-59375', 'CVE-2026-32776', 'CVE-2026-32777', 'CVE-2026-32778', 'CVE-2026-41080', 'CVE-2026-45186', 'CVE-2026-50219', 'CVE-2026-56403', 'CVE-2026-56404', 'CVE-2026-56405', 'CVE-2026-56408', 'CVE-2026-56412']},
    {'osver': '18.04', 'pkgname': 'libexpat1', 'pkgver': '2.2.5-3ubuntu0.9+esm4', 'cves': ['CVE-2025-59375', 'CVE-2026-32776', 'CVE-2026-32777', 'CVE-2026-32778', 'CVE-2026-41080', 'CVE-2026-45186', 'CVE-2026-50219', 'CVE-2026-56403', 'CVE-2026-56404', 'CVE-2026-56405', 'CVE-2026-56408', 'CVE-2026-56412']},
    {'osver': '20.04', 'pkgname': 'expat', 'pkgver': '2.2.9-1ubuntu0.8+esm2', 'cves': ['CVE-2025-59375', 'CVE-2026-32776', 'CVE-2026-32777', 'CVE-2026-32778', 'CVE-2026-41080', 'CVE-2026-45186', 'CVE-2026-50219', 'CVE-2026-56403', 'CVE-2026-56404', 'CVE-2026-56405', 'CVE-2026-56408', 'CVE-2026-56412']},
    {'osver': '20.04', 'pkgname': 'libexpat1', 'pkgver': '2.2.9-1ubuntu0.8+esm2', 'cves': ['CVE-2025-59375', 'CVE-2026-32776', 'CVE-2026-32777', 'CVE-2026-32778', 'CVE-2026-41080', 'CVE-2026-45186', 'CVE-2026-50219', 'CVE-2026-56403', 'CVE-2026-56404', 'CVE-2026-56405', 'CVE-2026-56408', 'CVE-2026-56412']},
    {'osver': '22.04', 'pkgname': 'expat', 'pkgver': '2.4.7-1ubuntu0.8', 'cves': ['CVE-2025-59375', 'CVE-2026-32776', 'CVE-2026-32777', 'CVE-2026-32778', 'CVE-2026-41080', 'CVE-2026-45186', 'CVE-2026-50219', 'CVE-2026-56403', 'CVE-2026-56404', 'CVE-2026-56405', 'CVE-2026-56408', 'CVE-2026-56412']},
    {'osver': '22.04', 'pkgname': 'libexpat1', 'pkgver': '2.4.7-1ubuntu0.8', 'cves': ['CVE-2025-59375', 'CVE-2026-32776', 'CVE-2026-32777', 'CVE-2026-32778', 'CVE-2026-41080', 'CVE-2026-45186', 'CVE-2026-50219', 'CVE-2026-56403', 'CVE-2026-56404', 'CVE-2026-56405', 'CVE-2026-56408', 'CVE-2026-56412']},
    {'osver': '24.04', 'pkgname': 'expat', 'pkgver': '2.6.1-2ubuntu0.5', 'cves': ['CVE-2025-59375', 'CVE-2026-32776', 'CVE-2026-32777', 'CVE-2026-32778', 'CVE-2026-41080', 'CVE-2026-45186', 'CVE-2026-50219', 'CVE-2026-56403', 'CVE-2026-56404', 'CVE-2026-56405', 'CVE-2026-56408', 'CVE-2026-56412']},
    {'osver': '24.04', 'pkgname': 'libexpat1', 'pkgver': '2.6.1-2ubuntu0.5', 'cves': ['CVE-2025-59375', 'CVE-2026-32776', 'CVE-2026-32777', 'CVE-2026-32778', 'CVE-2026-41080', 'CVE-2026-45186', 'CVE-2026-50219', 'CVE-2026-56403', 'CVE-2026-56404', 'CVE-2026-56405', 'CVE-2026-56408', 'CVE-2026-56412']},
    {'osver': '26.04', 'pkgname': 'expat', 'pkgver': '2.7.4-1ubuntu0.1', 'cves': ['CVE-2025-59375', 'CVE-2026-32776', 'CVE-2026-32777', 'CVE-2026-32778', 'CVE-2026-41080', 'CVE-2026-45186', 'CVE-2026-50219', 'CVE-2026-56403', 'CVE-2026-56404', 'CVE-2026-56405', 'CVE-2026-56408', 'CVE-2026-56412']},
    {'osver': '26.04', 'pkgname': 'libexpat1', 'pkgver': '2.7.4-1ubuntu0.1', 'cves': ['CVE-2025-59375', 'CVE-2026-32776', 'CVE-2026-32777', 'CVE-2026-32778', 'CVE-2026-41080', 'CVE-2026-45186', 'CVE-2026-50219', 'CVE-2026-56403', 'CVE-2026-56404', 'CVE-2026-56405', 'CVE-2026-56408', 'CVE-2026-56412']}
];

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_WARNING,
    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, 'expat / lib64expat1 / libexpat1');
}