Ubuntu 20.04 LTS / 22.04 LTS : Linux kernel vulnerability (USN-7862-1)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-7862-1. 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(274408);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/06/03");

  script_cve_id("CVE-2025-40300");
  script_xref(name:"USN", value:"7862-1");

  script_name(english:"Ubuntu 20.04 LTS / 22.04 LTS : Linux kernel vulnerability (USN-7862-1)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Ubuntu host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The remote Ubuntu 20.04 LTS / 22.04 LTS host has a package installed that is affected by a vulnerability as referenced
in the USN-7862-1 advisory.

    Jean-Claude Graf, Sandro Regge, Ali Hajiabadi, and Kaveh Razavi discovered that the Linux kernel
    contained insufficient branch predictor isolation between a guest and a userspace hypervisor for certain
    processors. This flaw is known as VMSCAPE. An attacker in a guest VM could possibly use this to expose
    sensitive information from the host OS.

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for this issue 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-7862-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected kernel package.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:S/C:N/I:N/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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-2025-40300");

  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:"2025/09/11");
  script_set_attribute(attribute:"patch_publication_date", value:"2025/11/06");
  script_set_attribute(attribute:"plugin_publication_date", value:"2025/11/07");

  script_set_attribute(attribute:"plugin_type", value:"local");
  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:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1079-gkeop");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1090-ibm");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1091-intel-iotg");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1091-nvidia");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1091-nvidia-lowlatency");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1092-gke");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1093-oracle");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1096-aws");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1096-aws-64k");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1096-gcp");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-161-generic");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-161-generic-64k");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-161-generic-lpae");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-161-lowlatency");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-161-lowlatency-64k");
  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) 2025-2026 Canonical, Inc. / NASL script (C) 2025-2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

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

  exit(0);
}

include('debian_package.inc');
include('ksplice.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 (! ('20.04' >< os_release || '22.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 20.04 / 22.04', '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 ubuntu_pro_detected = get_kb_item('Host/Ubuntu/Pro/Services/esm-apps');
ubuntu_pro_detected = !empty_or_null(ubuntu_pro_detected);

var kernel_mappings = {
  '20.04': {
    '5.15.0': {
      'generic': '5.15.0-161',
      'generic-64k': '5.15.0-161',
      'generic-lpae': '5.15.0-161',
      'lowlatency': '5.15.0-161',
      'lowlatency-64k': '5.15.0-161',
      'ibm': '5.15.0-1090',
      'intel-iotg': '5.15.0-1091',
      'oracle': '5.15.0-1093',
      'aws': '5.15.0-1096',
      'gcp': '5.15.0-1096'
    }
  },
  '22.04': {
    '5.15.0': {
      'generic': '5.15.0-161',
      'generic-64k': '5.15.0-161',
      'generic-lpae': '5.15.0-161',
      'lowlatency': '5.15.0-161',
      'lowlatency-64k': '5.15.0-161',
      'gkeop': '5.15.0-1079',
      'ibm': '5.15.0-1090',
      'intel-iotg': '5.15.0-1091',
      'nvidia': '5.15.0-1091',
      'nvidia-lowlatency': '5.15.0-1091',
      'gke': '5.15.0-1092',
      'oracle': '5.15.0-1093',
      'aws': '5.15.0-1096',
      'aws-64k': '5.15.0-1096',
      'gcp': '5.15.0-1096'
    }
  }
};

var host_kernel_release = get_kb_item('Host/uptrack-uname-r');
if (empty_or_null(host_kernel_release)) host_kernel_release = get_kb_item_or_exit('Host/uname-r');
var host_kernel_base_version = get_kb_item_or_exit('Host/Debian/kernel-base-version');
var host_kernel_type = get_kb_item_or_exit('Host/Debian/kernel-type');
if(empty_or_null(kernel_mappings[os_release][host_kernel_base_version][host_kernel_type])) audit(AUDIT_INST_VER_NOT_VULN, 'kernel ' + host_kernel_release);

var extra = '';
var kernel_fixed_version = kernel_mappings[os_release][host_kernel_base_version][host_kernel_type] + "-" + host_kernel_type;
if (!ubuntu_pro_detected) {
  extra += 'NOTE: This vulnerability check contains fixes that apply to packages only \n';
  extra += 'available in Ubuntu ESM repositories. Access to these package security updates \n';
  extra += 'require an Ubuntu Pro subscription.\n\n';
}
if (deb_ver_cmp(ver1:host_kernel_release, ver2:kernel_fixed_version) < 0)
{
  extra += 'Running Kernel level of ' + host_kernel_release + ' does not meet the minimum fixed level of ' + kernel_fixed_version + ' for this advisory.\n\n';
}
  else
{
  audit(AUDIT_PATCH_INSTALLED, 'Kernel package for USN-7862-1');
}

if (get_one_kb_item('Host/ksplice/kernel-cves'))
{
  var cve_list = make_list('CVE-2025-40300');
  if (ksplice_cves_check(cve_list))
  {
    audit(AUDIT_PATCH_INSTALLED, 'KSplice hotfix for USN-7862-1');
  }
  else
  {
    extra = extra + ksplice_reporting_text();
  }
}
if (extra) {
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : extra
  );
  exit(0);
}