Unity Linux 20.1050e Security Update: kernel (UTSA-2026-102137)

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

include('compat.inc');

if (description)
{
  script_id(337257);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/18");

  script_cve_id("CVE-2026-43496");

  script_name(english:"Unity Linux 20.1050e Security Update: kernel (UTSA-2026-102137)");

  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-2026-102137 advisory.

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

    net/sched: sch_red: Replace direct dequeue call with peek and qdisc_dequeue_peeked

    When red qdisc has children (eg qfq qdisc) whose peek() callback is
    qdisc_peek_dequeued(), we could get a kernel panic. When the parent of such
    qdiscs (eg illustrated in patch #3 as tbf) wants to retrieve an skb from
    its child (red in this case), it will do the following:
     1a. do a peek() - and when sensing there's an skb the child can offer, then
         - the child in this case(red) calls its child's (qfq) peek.
            qfq does the right thing and will return the gso_skb queue packet.
            Note: if there wasnt a gso_skb entry then qfq will store it there.
     1b. invoke a dequeue() on the child (red). And herein lies the problem.
         - red will call the child's dequeue() which will essentially just
           try to grab something of qfq's queue.

    [   78.667668][  T363] KASAN: null-ptr-deref in range [0x0000000000000048-0x000000000000004f]
    [   78.667927][  T363] CPU: 1 UID: 0 PID: 363 Comm: ping Not tainted 7.1.0-rc1-00033-g46f74a3f7d57-dirty
    #790 PREEMPT(full)
    [   78.668263][  T363] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
    [   78.668486][  T363] RIP: 0010:qfq_dequeue+0x446/0xc90 [sch_qfq]
    [   78.668718][  T363] Code: 54 c0 e8 dd 90 00 f1 48 c7 c7 e0 03 54 c0 48 89 de e8 ce 90 00 f1 48 8d 7b 48
    b8 ff ff 37 00 48 89 fa 48 c1 e0 2a 48 c1 ea 03 <80> 3c 02 00 74 05 e8 ef a1 e1 f1 48 8b 7b 48 48 8d 54 24
    58 48 8d
    [   78.669312][  T363] RSP: 0018:ffff88810de573e0 EFLAGS: 00010216
    [   78.669533][  T363] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
    [   78.669790][  T363] RDX: 0000000000000009 RSI: 0000000000000004 RDI: 0000000000000048
    [   78.670044][  T363] RBP: ffff888110dc4000 R08: ffffffffb1b0885a R09: fffffbfff6ba9078
    [   78.670297][  T363] R10: 0000000000000003 R11: ffff888110e31c80 R12: 0000001880000000
    [   78.670560][  T363] R13: ffff888110dc4150 R14: ffff888110dc42b8 R15: 0000000000000200
    [   78.670814][  T363] FS:  00007f66a8f09c40(0000) GS:ffff888163428000(0000) knlGS:0000000000000000
    [   78.671110][  T363] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    [   78.671324][  T363] CR2: 000055db4c6a30a8 CR3: 000000010da67000 CR4: 0000000000750ef0
    [   78.671585][  T363] PKRU: 55555554
    [   78.671713][  T363] Call Trace:
    [   78.671843][  T363]  <TASK>
    [   78.671936][  T363]  ? __pfx_qfq_dequeue+0x10/0x10 [sch_qfq]
    [   78.672148][  T363]  ? __pfx__printk+0x10/0x10
    [   78.672322][  T363]  ? srso_alias_return_thunk+0x5/0xfbef5
    [   78.672496][  T363]  ? lockdep_hardirqs_on_prepare+0xa8/0x1a0
    [   78.672706][  T363]  ? srso_alias_return_thunk+0x5/0xfbef5
    [   78.672875][  T363]  ? trace_hardirqs_on+0x19/0x1a0
    [   78.673047][  T363]  red_dequeue+0x65/0x270 [sch_red]
    [   78.673217][  T363]  ? srso_alias_return_thunk+0x5/0xfbef5
    [   78.673385][  T363]  tbf_dequeue.cold+0xb0/0x70c [sch_tbf]
    [   78.673566][  T363]  __qdisc_run+0x169/0x1900

    The right thing to do in #1b is to grab the skb off gso_skb queue.
    This patchset fixes that issue by changing #1b to use qdisc_dequeue_peeked()
    method instead.

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-2026-102137
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?7fa67cf4");
  # https://lore.kernel.org/linux-cve-announce/2026052157-CVE-2026-43496-07e1@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?56444866");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2026-43496");
  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-2026-43496");

  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:"2026/05/21");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/08/17");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/08/18");

  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-4.19.90-2211.5.0.0178.67.uel20', 'sp':'1050e', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2211.5.0.0178.67.uel20', 'sp':'1050e', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2211.5.0.0178.67.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_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');
}