Unity Linux 20.1050a / 20.1060a / 20.1070a Security Update: xorg-x11-server-Xwayland (UTSA-2026-147047)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(373831);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/29");

  script_cve_id("CVE-2026-50261");

  script_name(english:"Unity Linux 20.1050a / 20.1060a / 20.1070a Security Update: xorg-x11-server-Xwayland (UTSA-2026-147047)");

  script_set_attribute(attribute:"synopsis", value:
"The Unity Linux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the
UTSA-2026-147047 advisory.

    A use-after-free flaw was found in the X.Org X server and Xwayland in SyncChangeCounter(). A client that
    sets up multiple SyncCounters can trigger a use-after-free when destroying those counters via a second
    client connection while changing those counters. This may be used to crash the server, or for privilege
    escalation if the X server runs as root.

Tenable has extracted the preceding description block directly from the Unity 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.");
  # https://src.uniontech.com/#/security_advisory_detail?utsa_id=UTSA-2026-147047
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?c9b9dc3f");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:26562");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:26566");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:26590");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:26610");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:26709");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:28923");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:29844");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:36083");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:36085");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:36086");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:36087");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:36632");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:36633");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:36634");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:36768");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:36791");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:36792");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:36798");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:38502");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:38810");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:46377");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:46382");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:46385");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:46392");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:46456");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:46460");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:46473");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:49519");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/CVE-2026-50261");
  script_set_attribute(attribute:"see_also", value:"https://bugzilla.redhat.com/show_bug.cgi?id=2485386");
  # https://gitlab.freedesktop.org/xorg/xserver/-/commit/bdd7bf57af208b1ddf57d4683d67104443b44812
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?bac3dad2");
  script_set_attribute(attribute:"see_also", value:"https://lists.x.org/archives/xorg-announce/2026-June/003702.html");
  script_set_attribute(attribute:"see_also", value:"https://redhat.atlassian.net/browse/PSIRTSUPT-16950");
  script_set_attribute(attribute:"solution", value:
"Update the affected xorg-x11-server-Xwayland package.");
  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:U/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:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-50261");

  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:"2026/06/01");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/10/30");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/29");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Unity 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("ssh_get_info2.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/UOS-Server/release", "Host/UOS-Server/rpm-list", "Host/cpu");

  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) || 'UOS Server' >!< os_product) audit(AUDIT_OS_NOT, 'UOS Server');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'UOS Server');
if (! preg(pattern:"^(20.1050a|20.1060a|20.1070a)([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'UOS Server 20.1050a / 20.1060a / 20.1070a', 'UOS Server ' + os_version);

if (!get_kb_item('Host/UOS-Server/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('aarch64' >!< cpu && 'amd64' >!< cpu && 'loongarch64' >!< cpu && 'x86_64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'UOS Server', cpu);


var constraints = [
  {
    'release': '20',
    'sp': '1050a',
    'pkgs': [
      {'reference':'xorg-x11-server-Xwayland-24.1.9-4.uelc20.3', 'sp':'1050a', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'xorg-x11-server-Xwayland-24.1.9-4.uelc20.3', 'sp':'1050a', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'xorg-x11-server-Xwayland-24.1.9-4.uelc20.3', 'sp':'1050a', 'cpu':'loongarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'xorg-x11-server-Xwayland-24.1.9-4.uelc20.3', 'sp':'1050a', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE}
    ]
  },
  {
    'release': '20',
    'sp': '1060a',
    'pkgs': [
      {'reference':'xorg-x11-server-Xwayland-24.1.9-4.uelc20.3', 'sp':'1060a', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'xorg-x11-server-Xwayland-24.1.9-4.uelc20.3', 'sp':'1060a', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'xorg-x11-server-Xwayland-24.1.9-4.uelc20.3', 'sp':'1060a', 'cpu':'loongarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'xorg-x11-server-Xwayland-24.1.9-4.uelc20.3', 'sp':'1060a', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE}
    ]
  },
  {
    'release': '20',
    'sp': '1070a',
    'pkgs': [
      {'reference':'xorg-x11-server-Xwayland-24.1.9-4.uelc20.3', 'sp':'1070a', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'xorg-x11-server-Xwayland-24.1.9-4.uelc20.3', 'sp':'1070a', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'xorg-x11-server-Xwayland-24.1.9-4.uelc20.3', 'sp':'1070a', 'cpu':'loongarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'xorg-x11-server-Xwayland-24.1.9-4.uelc20.3', 'sp':'1070a', 'cpu':'x86_64', '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_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, 'xorg-x11-server-Xwayland');
}