Unity Linux 20.1050e Security Update: kernel (UTSA-2026-099977)

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

include('compat.inc');

if (description)
{
  script_id(336223);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/17");

  script_cve_id("CVE-2026-31450");

  script_name(english:"Unity Linux 20.1050e Security Update: kernel (UTSA-2026-099977)");

  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-2026-099977 advisory.

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

    ext4: publish jinode after initialization

    ext4_inode_attach_jinode() publishes ei->jinode to concurrent users.
    It used to set ei->jinode before jbd2_journal_init_jbd_inode(),
    allowing a reader to observe a non-NULL jinode with i_vfs_inode
    still unset.

    The fast commit flush path can then pass this jinode to
    jbd2_wait_inode_data(), which dereferences i_vfs_inode->i_mapping and
    may crash.

    Below is the crash I observe:
    ```
    BUG: unable to handle page fault for address: 000000010beb47f4
    PGD 110e51067 P4D 110e51067 PUD 0
    Oops: Oops: 0000 [#1] SMP NOPTI
    CPU: 1 UID: 0 PID: 4850 Comm: fc_fsync_bench_ Not tainted 6.18.0-00764-g795a690c06a5 #1 PREEMPT(voluntary)
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.17.0-2-2 04/01/2014
    RIP: 0010:xas_find_marked+0x3d/0x2e0
    Code: e0 03 48 83 f8 02 0f 84 f0 01 00 00 48 8b 47 08 48 89 c3 48 39 c6 0f 82 fd 01 00 00 48 85 c9 74 3d
    48 83 f9 03 77 63 4c 8b 0f <49> 8b 71 08 48 c7 47 18 00 00 00 00 48 89 f1 83 e1 03 48 83 f9 02
    RSP: 0018:ffffbbee806e7bf0 EFLAGS: 00010246
    RAX: 000000000010beb4 RBX: 000000000010beb4 RCX: 0000000000000003
    RDX: 0000000000000001 RSI: 0000002000300000 RDI: ffffbbee806e7c10
    RBP: 0000000000000001 R08: 0000002000300000 R09: 000000010beb47ec
    R10: ffff9ea494590090 R11: 0000000000000000 R12: 0000002000300000
    R13: ffffbbee806e7c90 R14: ffff9ea494513788 R15: ffffbbee806e7c88
    FS: 00007fc2f9e3e6c0(0000) GS:ffff9ea6b1444000(0000) knlGS:0000000000000000
    CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 000000010beb47f4 CR3: 0000000119ac5000 CR4: 0000000000750ef0
    PKRU: 55555554
    Call Trace:
    <TASK>
    filemap_get_folios_tag+0x87/0x2a0
    __filemap_fdatawait_range+0x5f/0xd0
    ? srso_alias_return_thunk+0x5/0xfbef5
    ? __schedule+0x3e7/0x10c0
    ? srso_alias_return_thunk+0x5/0xfbef5
    ? srso_alias_return_thunk+0x5/0xfbef5
    ? srso_alias_return_thunk+0x5/0xfbef5
    ? preempt_count_sub+0x5f/0x80
    ? srso_alias_return_thunk+0x5/0xfbef5
    ? cap_safe_nice+0x37/0x70
    ? srso_alias_return_thunk+0x5/0xfbef5
    ? preempt_count_sub+0x5f/0x80
    ? srso_alias_return_thunk+0x5/0xfbef5
    filemap_fdatawait_range_keep_errors+0x12/0x40
    ext4_fc_commit+0x697/0x8b0
    ? ext4_file_write_iter+0x64b/0x950
    ? srso_alias_return_thunk+0x5/0xfbef5
    ? preempt_count_sub+0x5f/0x80
    ? srso_alias_return_thunk+0x5/0xfbef5
    ? vfs_write+0x356/0x480
    ? srso_alias_return_thunk+0x5/0xfbef5
    ? preempt_count_sub+0x5f/0x80
    ext4_sync_file+0xf7/0x370
    do_fsync+0x3b/0x80
    ? syscall_trace_enter+0x108/0x1d0
    __x64_sys_fdatasync+0x16/0x20
    do_syscall_64+0x62/0x2c0
    entry_SYSCALL_64_after_hwframe+0x76/0x7e
    ...
    ```

    Fix this by initializing the jbd2_inode first.
    Use smp_wmb() and WRITE_ONCE() to publish ei->jinode after
    initialization. Readers use READ_ONCE() to fetch the pointer.

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-2026-099977
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?74ac006f");
  # https://lore.kernel.org/linux-cve-announce/2026042247-CVE-2026-31450-19fa@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?5d976294");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2026-31450");
  script_set_attribute(attribute:"solution", value:
"Update the affected kernel package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/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-2026-31450");

  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:"2026/04/22");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/08/13");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/08/17");

  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-5.10.0-27.18.uel20', 'sp':'1050e', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-27.18.uel20', 'sp':'1050e', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-27.18.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_HOLE,
      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');
}