Unity Linux 20.1050a Security Update: kernel (UTSA-2026-053346)

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

include('compat.inc');

if (description)
{
  script_id(343392);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/06");

  script_cve_id("CVE-2025-37834");

  script_name(english:"Unity Linux 20.1050a Security Update: kernel (UTSA-2026-053346)");

  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-2026-053346 advisory.

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

    mm/vmscan: don't try to reclaim hwpoison folio

    Syzkaller reports a bug as follows:

    Injecting memory failure for pfn 0x18b00e at process virtual address 0x20ffd000
    Memory failure: 0x18b00e: dirty swapcache page still referenced by 2 users
    Memory failure: 0x18b00e: recovery action for dirty swapcache page: Failed
    page: refcount:2 mapcount:0 mapping:0000000000000000 index:0x20ffd pfn:0x18b00e
    memcg:ffff0000dd6d9000
    anon flags: 0x5ffffe00482011(locked|dirty|arch_1|swapbacked|hwpoison|node=0|zone=2|lastcpupid=0xfffff)
    raw: 005ffffe00482011 dead000000000100 dead000000000122 ffff0000e232a7c9
    raw: 0000000000020ffd 0000000000000000 00000002ffffffff ffff0000dd6d9000
    page dumped because: VM_BUG_ON_FOLIO(!folio_test_uptodate(folio))
    ------------[ cut here ]------------
    kernel BUG at mm/swap_state.c:184!
    Internal error: Oops - BUG: 00000000f2000800 [#1] SMP
    Modules linked in:
    CPU: 0 PID: 60 Comm: kswapd0 Not tainted 6.6.0-gcb097e7de84e #3
    Hardware name: linux,dummy-virt (DT)
    pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
    pc : add_to_swap+0xbc/0x158
    lr : add_to_swap+0xbc/0x158
    sp : ffff800087f37340
    x29: ffff800087f37340 x28: fffffc00052c0380 x27: ffff800087f37780
    x26: ffff800087f37490 x25: ffff800087f37c78 x24: ffff800087f377a0
    x23: ffff800087f37c50 x22: 0000000000000000 x21: fffffc00052c03b4
    x20: 0000000000000000 x19: fffffc00052c0380 x18: 0000000000000000
    x17: 296f696c6f662865 x16: 7461646f7470755f x15: 747365745f6f696c
    x14: 6f6621284f494c4f x13: 0000000000000001 x12: ffff600036d8b97b
    x11: 1fffe00036d8b97a x10: ffff600036d8b97a x9 : dfff800000000000
    x8 : 00009fffc9274686 x7 : ffff0001b6c5cbd3 x6 : 0000000000000001
    x5 : ffff0000c25896c0 x4 : 0000000000000000 x3 : 0000000000000000
    x2 : 0000000000000000 x1 : ffff0000c25896c0 x0 : 0000000000000000
    Call trace:
     add_to_swap+0xbc/0x158
     shrink_folio_list+0x12ac/0x2648
     shrink_inactive_list+0x318/0x948
     shrink_lruvec+0x450/0x720
     shrink_node_memcgs+0x280/0x4a8
     shrink_node+0x128/0x978
     balance_pgdat+0x4f0/0xb20
     kswapd+0x228/0x438
     kthread+0x214/0x230
     ret_from_fork+0x10/0x20

    I can reproduce this issue with the following steps:

    1) When a dirty swapcache page is isolated by reclaim process and the
       page isn't locked, inject memory failure for the page.
       me_swapcache_dirty() clears uptodate flag and tries to delete from lru,
       but fails.  Reclaim process will put the hwpoisoned page back to lru.

    2) The process that maps the hwpoisoned page exits, the page is deleted
       the page will never be freed and will be in the lru forever.

    3) If we trigger a reclaim again and tries to reclaim the page,
       add_to_swap() will trigger VM_BUG_ON_FOLIO due to the uptodate flag is
       cleared.

    To fix it, skip the hwpoisoned page in shrink_folio_list().  Besides, the
    hwpoison folio may not be unmapped by hwpoison_user_mappings() yet, unmap
    it in shrink_folio_list(), otherwise the folio will fail to be unmaped by
    hwpoison_user_mappings() since the folio isn't in lru list.

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-2026-053346
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?cc22e70d");
  # https://lore.kernel.org/linux-cve-announce/2025050825-CVE-2025-37834-269b@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?49a1ee99");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2025-37834");
  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-2025-37834");

  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:"2025/05/08");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/07/27");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/06");

  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)([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'UOS Server 20.1050a', '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':'kernel-4.19.0-91.82.132.24.uelc20', 'sp':'1050a', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.0-91.82.132.24.uelc20', 'sp':'1050a', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.0-91.82.132.24.uelc20', 'sp':'1050a', 'cpu':'loongarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.0-91.82.132.24.uelc20', 'sp':'1050a', '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');
}