Unity Linux 20.1050e / 20.1060e / 20.1070e Security Update: kernel (UTSA-2026-107268)

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

include('compat.inc');

if (description)
{
  script_id(344969);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/11");

  script_cve_id("CVE-2025-37856");

  script_name(english:"Unity Linux 20.1050e / 20.1060e / 20.1070e Security Update: kernel (UTSA-2026-107268)");

  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-2026-107268 advisory.

    In the Linux kernel, the following vulnerability has been resolved:

    btrfs: harden block_group::bg_list against list_del() races

    As far as I can tell, these calls of list_del_init() on bg_list cannot
    run concurrently with btrfs_mark_bg_unused() or btrfs_mark_bg_to_reclaim(),
    as they are in transaction error paths and situations where the block
    group is readonly.

    However, if there is any chance at all of racing with mark_bg_unused(),
    or a different future user of bg_list, better to be safe than sorry.

    Otherwise we risk the following interleaving (bg_list refcount in parens)

    T1 (some random op)                       T2 (btrfs_mark_bg_unused)
                                            !list_empty(&bg->bg_list); (1)
    list_del_init(&bg->bg_list); (1)
                                            list_move_tail (1)
    btrfs_put_block_group (0)
                                            btrfs_delete_unused_bgs
                                                 bg = list_first_entry
                                                 list_del_init(&bg->bg_list);
                                                 btrfs_put_block_group(bg); (-1)

    Ultimately, this results in a broken ref count that hits zero one deref
    early and the real final deref underflows the refcount, resulting in a WARNING.

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-2026-107268
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?69c9823e");
  # https://git.kernel.org/stable/c/185fd73e5ac06027c4be9a129e59193f6a3ef202
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?d5074dfe");
  # https://git.kernel.org/stable/c/7511e29cf1355b2c47d0effb39e463119913e2f6
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?c7e1f026");
  # https://git.kernel.org/stable/c/909e60fb469d4101c6b08cf6e622efb062bb24a1
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?d1606e0f");
  # https://git.kernel.org/stable/c/bf089c4d1141b27332c092b1dcca5022c415a3b6
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?27c288a4");
  # https://lore.kernel.org/linux-cve-announce/2025050921-CVE-2025-37856-3117@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?6eace392");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2025-37856");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2025-37856");
  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-2025-37856");

  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:"2025/05/09");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/09/11");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/11");

  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:"^(20.1050e|20.1060e|20.1070e)([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'UOS Server 20.1050e / 20.1060e / 20.1070e', '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 && 'x86_64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'UOS Server', cpu);


var constraints = [
  {
    'release': '20',
    'sp': '1050e',
    'pkgs': [
      {'reference':'kernel-4.19.90-2305.1.0.0199.122.uel20', 'sp':'1050e', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2305.1.0.0199.122.uel20', 'sp':'1050e', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2305.1.0.0199.122.uel20', 'sp':'1050e', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE}
    ]
  },
  {
    'release': '20',
    'sp': '1060e',
    'pkgs': [
      {'reference':'kernel-4.19.90-2311.4.0.0227.122.uel20', 'sp':'1060e', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2311.4.0.0227.122.uel20', 'sp':'1060e', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2311.4.0.0227.122.uel20', 'sp':'1060e', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE}
    ]
  },
  {
    'release': '20',
    'sp': '1070e',
    'pkgs': [
      {'reference':'kernel-4.19.90-2601.1.0.0023.uel20', 'sp':'1070e', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2601.1.0.0023.uel20', 'sp':'1070e', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2601.1.0.0023.uel20', 'sp':'1070e', '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, 'kernel');
}