Unity Linux 20.1070a Security Update: kernel (UTSA-2026-013658)

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

include('compat.inc');

if (description)
{
  script_id(309545);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/04/22");

  script_cve_id("CVE-2023-53692");

  script_name(english:"Unity Linux 20.1070a Security Update: kernel (UTSA-2026-013658)");

  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-2026-013658 advisory.

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

    ext4: fix use-after-free read in ext4_find_extent for bigalloc + inline

    Syzbot found the following issue:
    loop0: detected capacity change from 0 to 2048
    EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode:
    none.
    ==================================================================
    BUG: KASAN: use-after-free in ext4_ext_binsearch_idx fs/ext4/extents.c:768 [inline]
    BUG: KASAN: use-after-free in ext4_find_extent+0x76e/0xd90 fs/ext4/extents.c:931
    Read of size 4 at addr ffff888073644750 by task syz-executor420/5067

    CPU: 0 PID: 5067 Comm: syz-executor420 Not tainted 6.2.0-rc1-syzkaller #0
    Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
    Call Trace:
     <TASK>
     __dump_stack lib/dump_stack.c:88 [inline]
     dump_stack_lvl+0x1b1/0x290 lib/dump_stack.c:106
     print_address_description+0x74/0x340 mm/kasan/report.c:306
     print_report+0x107/0x1f0 mm/kasan/report.c:417
     kasan_report+0xcd/0x100 mm/kasan/report.c:517
     ext4_ext_binsearch_idx fs/ext4/extents.c:768 [inline]
     ext4_find_extent+0x76e/0xd90 fs/ext4/extents.c:931
     ext4_clu_mapped+0x117/0x970 fs/ext4/extents.c:5809
     ext4_insert_delayed_block fs/ext4/inode.c:1696 [inline]
     ext4_da_map_blocks fs/ext4/inode.c:1806 [inline]
     ext4_da_get_block_prep+0x9e8/0x13c0 fs/ext4/inode.c:1870
     ext4_block_write_begin+0x6a8/0x2290 fs/ext4/inode.c:1098
     ext4_da_write_begin+0x539/0x760 fs/ext4/inode.c:3082
     generic_perform_write+0x2e4/0x5e0 mm/filemap.c:3772
     ext4_buffered_write_iter+0x122/0x3a0 fs/ext4/file.c:285
     ext4_file_write_iter+0x1d0/0x18f0
     call_write_iter include/linux/fs.h:2186 [inline]
     new_sync_write fs/read_write.c:491 [inline]
     vfs_write+0x7dc/0xc50 fs/read_write.c:584
     ksys_write+0x177/0x2a0 fs/read_write.c:637
     do_syscall_x64 arch/x86/entry/common.c:50 [inline]
     do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
     entry_SYSCALL_64_after_hwframe+0x63/0xcd
    RIP: 0033:0x7f4b7a9737b9
    RSP: 002b:00007ffc5cac3668 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
    RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4b7a9737b9
    RDX: 00000000175d9003 RSI: 0000000020000200 RDI: 0000000000000004
    RBP: 00007f4b7a933050 R08: 0000000000000000 R09: 0000000000000000
    R10: 000000000000079f R11: 0000000000000246 R12: 00007f4b7a9330e0
    R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
     </TASK>

    Above issue is happens when enable bigalloc and inline data feature. As
    commit 131294c35ed6 fixed delayed allocation bug in ext4_clu_mapped for
    bigalloc + inline. But it only resolved issue when has inline data, if
    inline data has been converted to extent(ext4_da_convert_inline_data_to_extent)
    before writepages, there is no EXT4_STATE_MAY_INLINE_DATA flag. However
    i_data is still store inline data in this scene. Then will trigger UAF
    when find extent.
    To resolve above issue, there is need to add judge ext4_has_inline_data(inode)
    in ext4_clu_mapped().

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-2026-013658
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?3f62a687");
  # https://lore.kernel.org/linux-cve-announce/2025102210-CVE-2023-53692-be2d@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?45afb34e");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2023-53692");
  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-2023-53692");

  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:"2023/06/07");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/04/22");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/04/22");

  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:"^20.1070a([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'UOS Server 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': '1070a',
    'pkgs': [
      {'reference':'kernel-5.10.0-56', 'sp':'1070a', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-56', 'sp':'1070a', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-56', 'sp':'1070a', 'cpu':'loongarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-56', '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, 'kernel');
}