Unity Linux 20.1050e Security Update: kernel (UTSA-2026-021574)

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

include('compat.inc');

if (description)
{
  script_id(315783);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/05/20");

  script_cve_id("CVE-2023-53178");

  script_name(english:"Unity Linux 20.1050e Security Update: kernel (UTSA-2026-021574)");

  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-2026-021574 advisory.

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

    mm: fix zswap writeback race condition

    The zswap writeback mechanism can cause a race condition resulting in
    memory corruption, where a swapped out page gets swapped in with data that
    was written to a different page.

    The race unfolds like this:
    1. a page with data A and swap offset X is stored in zswap
    2. page A is removed off the LRU by zpool driver for writeback in
       zswap-shrink work, data for A is mapped by zpool driver
    3. user space program faults and invalidates page entry A, offset X is
       considered free
    4. kswapd stores page B at offset X in zswap (zswap could also be
       full, if so, page B would then be IOed to X, then skip step 5.)
    5. entry A is replaced by B in tree->rbroot, this doesn't affect the
       local reference held by zswap-shrink work
    6. zswap-shrink work writes back A at X, and frees zswap entry A
    7. swapin of slot X brings A in memory instead of B

    The fix:
    Once the swap page cache has been allocated (case ZSWAP_SWAPCACHE_NEW),
    zswap-shrink work just checks that the local zswap_entry reference is
    still the same as the one in the tree.  If it's not the same it means that
    it's either been invalidated or replaced, in both cases the writeback is
    aborted because the local entry contains stale data.

    Reproducer:
    I originally found this by running `stress` overnight to validate my work
    on the zswap writeback mechanism, it manifested after hours on my test
    machine.  The key to make it happen is having zswap writebacks, so
    whatever setup pumps /sys/kernel/debug/zswap/written_back_pages should do
    the trick.

    In order to reproduce this faster on a vm, I setup a system with ~100M of
    available memory and a 500M swap file, then running `stress --vm 1
    --vm-bytes 300000000 --vm-stride 4000` makes it happen in matter of tens
    of minutes.  One can speed things up even more by swinging
    /sys/module/zswap/parameters/max_pool_percent up and down between, say, 20
    and 1; this makes it reproduce in tens of seconds.  It's crucial to set
    `--vm-stride` to something other than 4096 otherwise `stress` won't
    realize that memory has been corrupted because all pages would have the
    same data.

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-2026-021574
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?7daac924");
  # https://lore.kernel.org/linux-cve-announce/2025091555-CVE-2023-53178-9d27@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?c49657a2");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2023-53178");
  script_set_attribute(attribute:"solution", value:
"Update the affected kernel package.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:H/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:H/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-2023-53178");

  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:"2023/06/27");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/05/21");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/05/20");

  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([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'UOS Server 20.1050e', '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-4.19.90-2211.5.0.0178.56.uel20', 'sp':'1050e', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2211.5.0.0178.56.uel20', 'sp':'1050e', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2211.5.0.0178.56.uel20', 'sp':'1050e', '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_NOTE,
      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');
}