Oracle Linux 8 : Unbreakable Enterprise kernel (ELSA-2026-50353)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Oracle Linux Security Advisory ELSA-2026-50353.
##

include('compat.inc');

if (description)
{
  script_id(323959);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/06/30");

  script_cve_id("CVE-2026-52943");

  script_name(english:"Oracle Linux 8 : Unbreakable Enterprise kernel (ELSA-2026-50353)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Oracle Linux host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The remote Oracle Linux 8 host has packages installed that are affected by a vulnerability as referenced in the
ELSA-2026-50353 advisory.

    [5.4.17-2136.356.4.3]
    - net: skbuff: fix missing zerocopy reference in pskb_carve helpers (Minh Nguyen)  [Orabug: 39639989]
    {CVE-2026-52943}

    Credit Statement:
    The following people reported security vulnerabilities addressed by this ELSA to Oracle:
    Minh Nguyen <[email protected]> CVE-2026-52943

Tenable has extracted the preceding description block directly from the Oracle Linux 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://linux.oracle.com/errata/ELSA-2026-50353.html");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:S/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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-2026-52943");

  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:"2026/06/24");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/06/28");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/06/30");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:oracle:linux:8");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-container");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-container-debug");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-debug");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-debug-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:oracle:linux:kernel-uek-doc");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Oracle 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("linux_alt_patch_detect.nasl", "ssh_get_info.nasl");
  script_require_keys("Host/OracleLinux", "Host/RedHat/release", "Host/RedHat/rpm-list", "Host/local_checks_enabled");

  exit(0);
}


include('rpm2.inc');
include('ksplice.inc');

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) || !pregmatch(pattern: "Oracle (?:Linux Server|Enterprise Linux)", string:os_product)) audit(AUDIT_OS_NOT, 'Oracle Linux');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'Oracle Linux');
if (! preg(pattern:"^8([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'Oracle Linux 8.x', 'Oracle Linux ' + os_version);

if (!get_kb_item('Host/RedHat/rpm-list')) 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$" && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Oracle Linux', cpu);

var machine_uptrack_level = get_one_kb_item('Host/livepatch-kernel-version');
var livepatch_source = get_one_kb_item('Host/livepatch-kernel-source');
if (empty_or_null(livepatch_source)) livepatch_source = 'KSplice';

if (machine_uptrack_level)
{
  var trimmed_uptrack_level = ereg_replace(string:machine_uptrack_level, pattern:"\.(x86_64|i[3-6]86|aarch64)$", replace:'');
  var fixed_uptrack_levels = ['5.4.17-2136.356.4.3.el8uek'];
  foreach var fixed_uptrack_level ( fixed_uptrack_levels ) {
    if (rpm_spec_vers_cmp(a:trimmed_uptrack_level, b:fixed_uptrack_level) >= 0)
    {
      audit(AUDIT_PATCH_INSTALLED, livepatch_source + ' hotfix for ELSA-2026-50353');
    }
  }
  __rpm_report = 'Running ' + livepatch_source + ' level of ' + trimmed_uptrack_level + ' does not meet the minimum fixed level of ' + join(fixed_uptrack_levels, sep:' / ') + ' for this advisory.\n\n';
}

var kernel_major_minor = get_kb_item('Host/uname/major_minor');
if (empty_or_null(kernel_major_minor)) exit(1, 'Unable to determine kernel major-minor level.');
var expected_kernel_major_minor = '5.4';
if (kernel_major_minor != expected_kernel_major_minor)
  audit(AUDIT_OS_NOT, 'running kernel level ' + expected_kernel_major_minor + ', it is running kernel level ' + kernel_major_minor);

var constraints = [
  {
    'release': '8',
    'pkgs': [
      {'reference':'kernel-uek-5.4.17-2136.356.4.3.el8uek', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-5.4.17'},
      {'reference':'kernel-uek-debug-5.4.17-2136.356.4.3.el8uek', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-5.4.17'},
      {'reference':'kernel-uek-debug-devel-5.4.17-2136.356.4.3.el8uek', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-devel-5.4.17'},
      {'reference':'kernel-uek-devel-5.4.17-2136.356.4.3.el8uek', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-devel-5.4.17'},
      {'reference':'kernel-uek-5.4.17-2136.356.4.3.el8uek', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-5.4.17'},
      {'reference':'kernel-uek-container-5.4.17-2136.356.4.3.el8uek', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-container-5.4.17'},
      {'reference':'kernel-uek-container-debug-5.4.17-2136.356.4.3.el8uek', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-container-debug-5.4.17'},
      {'reference':'kernel-uek-debug-5.4.17-2136.356.4.3.el8uek', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-5.4.17'},
      {'reference':'kernel-uek-debug-devel-5.4.17-2136.356.4.3.el8uek', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-debug-devel-5.4.17'},
      {'reference':'kernel-uek-devel-5.4.17-2136.356.4.3.el8uek', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-devel-5.4.17'},
      {'reference':'kernel-uek-doc-5.4.17-2136.356.4.3.el8uek', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'kernel-uek-doc-5.4.17'}
    ]
  }
];

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_WARNING,
      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, 'kernel-uek / kernel-uek-container / kernel-uek-container-debug / etc');
}