Fedora 43 : xen (2026-9b1af4c793)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##
# The descriptive text and package checks in this plugin were
# extracted from Fedora Security Advisory FEDORA-2026-9b1af4c793
#

include('compat.inc');

if (description)
{
  script_id(334454);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/11");

  script_cve_id(
    "CVE-2025-10263",
    "CVE-2026-42487",
    "CVE-2026-42488",
    "CVE-2026-42489",
    "CVE-2026-42490",
    "CVE-2026-42492",
    "CVE-2026-42493",
    "CVE-2026-42494",
    "CVE-2026-42495",
    "CVE-2026-62423",
    "CVE-2026-62424",
    "CVE-2026-62425",
    "CVE-2026-62426",
    "CVE-2026-62427",
    "CVE-2026-62428",
    "CVE-2026-62429",
    "CVE-2026-62430",
    "CVE-2026-62431",
    "CVE-2026-62432",
    "CVE-2026-62433",
    "CVE-2026-62434",
    "CVE-2026-62435",
    "CVE-2026-62436"
  );
  script_xref(name:"IAVB", value:"2026-B-0151");
  script_xref(name:"FEDORA", value:"2026-9b1af4c793");

  script_name(english:"Fedora 43 : xen (2026-9b1af4c793)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Fedora host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Fedora 43 host has a package installed that is affected by multiple vulnerabilities as referenced in the
FEDORA-2026-9b1af4c793 advisory.

    update to xen 4.20.4
    includes security fixes
    x86 shadow paging is deprecated [XSA-495, CVE-2026-42493]
    vIRQ event channel binding may break Xenstore [XSA-496, CVE-2026-42492]
    buffer overruns in libfsimage iso9660 handling [XSA-497, CVE-2026-42494,
    CVE-2026-42495, CVE-2026-62423, CVE-2026-62424, CVE-2026-62425]
    sysctl and platform-op locks open to abuse [XSA-499, CVE-2026-62426,
    CVE-2026-62427]
    grant-table: type confusion in grant-copy [XSA-500, CVE-2026-62428]
    grant-table: version change racing with other operations [XSA-501,
    CVE-2026-62435, CVE-2026-62436]
    vNUMA domain cleanup may race other operations [XSA-502, CVE-2026-62429]
    x86: Out-of-bounds read in vRTC emulation [XSA-503, CVE-2026-62430]
    Viridian STIMER division by zero [XSA-504, CVE-2026-62431]
    evtchn: Race between FIFO expand and reset [XSA-505, CVE-2026-62432]
    correct buffer checks for DM_OP hypercalls [XSA-506, CVE-2026-62433]
    PoD: Don't try to reclaim special pages [XSA-507, CVE-2026-62434]
    pygrub is only supported in de-privileged mode [XSA-508]
    x86 HVM I/O port list traversal [XSA-491, CVE-2026-42487]
    domctl lock open to abuse [XSA-492, CVE-2026-42489, CVE-2026-42490]
    Arm: Completion of memory accesses not guaranteed by completion of a TLBI
    [XSA-493, CVE-2025-10263]
    x86: mismatched mapcache metadata [XSA-494, CVE-2026-42488]

Tenable has extracted the preceding description block directly from the Fedora 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://bodhi.fedoraproject.org/updates/FEDORA-2026-9b1af4c793");
  script_set_attribute(attribute:"solution", value:
"Update the affected xen package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:L/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-2025-10263");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2026-62427");

  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:"2026/06/09");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/07/30");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/08/11");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:43");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:xen");
  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:"Fedora Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/RedHat/release", "Host/RedHat/rpm-list");

  exit(0);
}


include('rpm2.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) || 'Fedora' >!< os_product) audit(AUDIT_OS_NOT, 'Fedora');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'Fedora');
if (! preg(pattern:"^43([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'Fedora 43', 'Fedora ' + 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$" && 's390' >!< cpu && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Fedora', cpu);

var constraints = [
  {
    'release': '43',
    'pkgs': [
      {'reference':'xen-4.20.4-1.fc43', 'rpm_spec_vers_cmp':TRUE}
    ]
  }
];

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_HOLE,
      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, 'xen');
}