Ubuntu 18.04 LTS / 24.04 LTS : dracut vulnerabilities (USN-8828-1)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-8828-1. 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(350946);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/29");

  script_cve_id("CVE-2026-6893", "CVE-2026-15816");
  script_xref(name:"USN", value:"8828-1");

  script_name(english:"Ubuntu 18.04 LTS / 24.04 LTS : dracut vulnerabilities (USN-8828-1)");

  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 18.04 LTS / 24.04 LTS host has packages installed that are affected by multiple vulnerabilities as
referenced in the USN-8828-1 advisory.

    It was discovered that dracut created initramfs images with overly permissive permissions under certain
    circumstances. A local attacker could possibly use this issue to obtain sensitive information. This issue
    only affected Ubuntu 16.04 LTS. (CVE-2016-8637)

    It was discovered that dracut did not properly sanitize DHCP options before writing them to shell scripts
    under certain circumstances. A remote attacker controlling a DHCP server on the local network could
    possibly use this issue to execute arbitrary code as root during system boot. This issue only affected
    Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, and Ubuntu 24.04 LTS.
    (CVE-2026-6893)

    It was discovered that dracut did not properly quote error messages written to shell scripts under certain
    circumstances. A remote attacker controlling a DHCP server on the local network could possibly use this
    issue to execute arbitrary code as root during system boot. This issue only affected Ubuntu 16.04 LTS,
    Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, and Ubuntu 24.04 LTS. (CVE-2026-15816)

    It was discovered that dracut did not properly sanitize network configuration data before writing it to a
    temporary shell script under certain circumstances. A remote attacker controlling DHCP on the local
    network could possibly use this issue to execute arbitrary code as root during system boot. This issue
    only affected Ubuntu 22.04 LTS. (CVE-2026-16445)

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-8828-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:A/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-6893");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/06/10");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/09/28");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/29");

  script_set_attribute(attribute:"plugin_type", value:"local");
  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:24.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:dracut");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:dracut-config-generic");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:dracut-config-rescue");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:dracut-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:dracut-install");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:dracut-live");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:dracut-network");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:dracut-squash");
  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 (! ('18.04' >< os_release || '24.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 18.04 / 24.04', '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': '18.04', 'pkgname': 'dracut', 'pkgver': '047-2ubuntu0.1~esm1', 'cves': ['CVE-2026-6893', 'CVE-2026-15816']},
    {'osver': '18.04', 'pkgname': 'dracut-config-generic', 'pkgver': '047-2ubuntu0.1~esm1', 'cves': ['CVE-2026-6893', 'CVE-2026-15816']},
    {'osver': '18.04', 'pkgname': 'dracut-config-rescue', 'pkgver': '047-2ubuntu0.1~esm1', 'cves': ['CVE-2026-6893', 'CVE-2026-15816']},
    {'osver': '18.04', 'pkgname': 'dracut-core', 'pkgver': '047-2ubuntu0.1~esm1', 'cves': ['CVE-2026-6893', 'CVE-2026-15816']},
    {'osver': '18.04', 'pkgname': 'dracut-network', 'pkgver': '047-2ubuntu0.1~esm1', 'cves': ['CVE-2026-6893', 'CVE-2026-15816']},
    {'osver': '24.04', 'pkgname': 'dracut', 'pkgver': '060+5-1ubuntu3.4', 'cves': ['CVE-2026-6893', 'CVE-2026-15816']},
    {'osver': '24.04', 'pkgname': 'dracut-config-generic', 'pkgver': '060+5-1ubuntu3.4', 'cves': ['CVE-2026-6893', 'CVE-2026-15816']},
    {'osver': '24.04', 'pkgname': 'dracut-config-rescue', 'pkgver': '060+5-1ubuntu3.4', 'cves': ['CVE-2026-6893', 'CVE-2026-15816']},
    {'osver': '24.04', 'pkgname': 'dracut-core', 'pkgver': '060+5-1ubuntu3.4', 'cves': ['CVE-2026-6893', 'CVE-2026-15816']},
    {'osver': '24.04', 'pkgname': 'dracut-install', 'pkgver': '060+5-1ubuntu3.4', 'cves': ['CVE-2026-6893', 'CVE-2026-15816']},
    {'osver': '24.04', 'pkgname': 'dracut-live', 'pkgver': '060+5-1ubuntu3.4', 'cves': ['CVE-2026-6893', 'CVE-2026-15816']},
    {'osver': '24.04', 'pkgname': 'dracut-network', 'pkgver': '060+5-1ubuntu3.4', 'cves': ['CVE-2026-6893', 'CVE-2026-15816']},
    {'osver': '24.04', 'pkgname': 'dracut-squash', 'pkgver': '060+5-1ubuntu3.4', 'cves': ['CVE-2026-6893', 'CVE-2026-15816']}
];

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, 'dracut / dracut-config-generic / dracut-config-rescue / dracut-core / etc');
}