Unity Linux 20.1050e / 20.1070e Security Update: kernel (UTSA-2026-011333)

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

include('compat.inc');

if (description)
{
  script_id(308857);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/04/22");

  script_cve_id("CVE-2023-53747");

  script_name(english:"Unity Linux 20.1050e / 20.1070e Security Update: kernel (UTSA-2026-011333)");

  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-2026-011333 advisory.

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

    vc_screen: reload load of struct vc_data pointer in vcs_write() to avoid UAF

    After a call to console_unlock() in vcs_write() the vc_data struct can be
    freed by vc_port_destruct(). Because of that, the struct vc_data pointer
    must be reloaded in the while loop in vcs_write() after console_lock() to
    avoid a UAF when vcs_size() is called.

    Syzkaller reported a UAF in vcs_size().

    BUG: KASAN: slab-use-after-free in vcs_size (drivers/tty/vt/vc_screen.c:215)
    Read of size 4 at addr ffff8880beab89a8 by task repro_vcs_size/4119

    Call Trace:
     <TASK>
    __asan_report_load4_noabort (mm/kasan/report_generic.c:380)
    vcs_size (drivers/tty/vt/vc_screen.c:215)
    vcs_write (drivers/tty/vt/vc_screen.c:664)
    vfs_write (fs/read_write.c:582 fs/read_write.c:564)
    ...
     <TASK>

    Allocated by task 1213:
    kmalloc_trace (mm/slab_common.c:1064)
    vc_allocate (./include/linux/slab.h:559 ./include/linux/slab.h:680
        drivers/tty/vt/vt.c:1078 drivers/tty/vt/vt.c:1058)
    con_install (drivers/tty/vt/vt.c:3334)
    tty_init_dev (drivers/tty/tty_io.c:1303 drivers/tty/tty_io.c:1415
        drivers/tty/tty_io.c:1392)
    tty_open (drivers/tty/tty_io.c:2082 drivers/tty/tty_io.c:2128)
    chrdev_open (fs/char_dev.c:415)
    do_dentry_open (fs/open.c:921)
    vfs_open (fs/open.c:1052)
    ...

    Freed by task 4116:
    kfree (mm/slab_common.c:1016)
    vc_port_destruct (drivers/tty/vt/vt.c:1044)
    tty_port_destructor (drivers/tty/tty_port.c:296)
    tty_port_put (drivers/tty/tty_port.c:312)
    vt_disallocate_all (drivers/tty/vt/vt_ioctl.c:662 (discriminator 2))
    vt_ioctl (drivers/tty/vt/vt_ioctl.c:903)
    tty_ioctl (drivers/tty/tty_io.c:2778)
    ...

    The buggy address belongs to the object at ffff8880beab8800
     which belongs to the cache kmalloc-1k of size 1024
    The buggy address is located 424 bytes inside of
     freed 1024-byte region [ffff8880beab8800, ffff8880beab8c00)

    The buggy address belongs to the physical page:
    page:00000000afc77580 refcount:1 mapcount:0 mapping:0000000000000000
        index:0x0 pfn:0xbeab8
    head:00000000afc77580 order:3 entire_mapcount:0 nr_pages_mapped:0
        pincount:0
    flags: 0xfffffc0010200(slab|head|node=0|zone=1|lastcpupid=0x1fffff)
    page_type: 0xffffffff()
    raw: 000fffffc0010200 ffff888100042dc0 ffffea000426de00 dead000000000002
    raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
    page dumped because: kasan: bad access detected

    Memory state around the buggy address:
     ffff8880beab8880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
     ffff8880beab8900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
    >ffff8880beab8980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                      ^
     ffff8880beab8a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
     ffff8880beab8a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
    ==================================================================
    Disabling lock debugging due to kernel taint

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-2026-011333
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?668c4139");
  # https://lore.kernel.org/linux-cve-announce/2025120842-CVE-2023-53747-ae4a@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?a3ea1e48");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2023-53747");
  script_set_attribute(attribute:"solution", value:
"Update the affected kernel package.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:H/Au:M/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:H/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-2023-53747");

  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:"2021/07/21");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/04/20");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/04/21");

  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|20.1070e([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'UOS Server 20.1050e / 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-5.10.0-27.5', 'sp':'1050e', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-27.5', 'sp':'1050e', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-27.5', 'sp':'1050e', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE}
    ]
  },
  {
    'release': '20',
    'sp': '1070e',
    'pkgs': [
      {'reference':'kernel-5.10.0-79.10', 'sp':'1070e', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-79.10', 'sp':'1070e', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-79.10', '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_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');
}