Unity Linux 20.1050e Security Update: kernel (UTSA-2026-006745)

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

include('compat.inc');

if (description)
{
  script_id(305547);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/04/08");

  script_cve_id("CVE-2026-22976");

  script_name(english:"Unity Linux 20.1050e Security Update: kernel (UTSA-2026-006745)");

  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-2026-006745 advisory.

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

    net/sched: sch_qfq: Fix NULL deref when deactivating inactive aggregate in qfq_reset

    `qfq_class->leaf_qdisc->q.qlen > 0` does not imply that the class
    itself is active.

    Two qfq_class objects may point to the same leaf_qdisc. This happens
    when:

    1. one QFQ qdisc is attached to the dev as the root qdisc, and

    2. another QFQ qdisc is temporarily referenced (e.g., via qdisc_get()
    / qdisc_put()) and is pending to be destroyed, as in function
    tc_new_tfilter.

    When packets are enqueued through the root QFQ qdisc, the shared
    leaf_qdisc->q.qlen increases. At the same time, the second QFQ
    qdisc triggers qdisc_put and qdisc_destroy: the qdisc enters
    qfq_reset() with its own q->q.qlen == 0, but its class's leaf
    qdisc->q.qlen > 0. Therefore, the qfq_reset would wrongly deactivate
    an inactive aggregate and trigger a null-deref in qfq_deactivate_agg:

    [    0.903172] BUG: kernel NULL pointer dereference, address: 0000000000000000
    [    0.903571] #PF: supervisor write access in kernel mode
    [    0.903860] #PF: error_code(0x0002) - not-present page
    [    0.904177] PGD 10299b067 P4D 10299b067 PUD 10299c067 PMD 0
    [    0.904502] Oops: Oops: 0002 [#1] SMP NOPTI
    [    0.904737] CPU: 0 UID: 0 PID: 135 Comm: exploit Not tainted 6.19.0-rc3+ #2 NONE
    [    0.905157] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
    rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014
    [    0.905754] RIP: 0010:qfq_deactivate_agg (include/linux/list.h:992 (discriminator 2)
    include/linux/list.h:1006 (discriminator 2) net/sched/sch_qfq.c:1367 (discriminator 2)
    net/sched/sch_qfq.c:1393 (discriminator 2))
    [    0.906046] Code: 0f 84 4d 01 00 00 48 89 70 18 8b 4b 10 48 c7 c2 ff ff ff ff 48 8b 78 08 48 d3 e2 48
    21 f2 48 2b 13 48 8b 30 48 d3 ea 8b 4b 18 0

    Code starting with the faulting instruction
    ===========================================
       0:   0f 84 4d 01 00 00       je     0x153
       6:   48 89 70 18             mov    %rsi,0x18(%rax)
       a:   8b 4b 10                mov    0x10(%rbx),%ecx
       d:   48 c7 c2 ff ff ff ff    mov    $0xffffffffffffffff,%rdx
      14:   48 8b 78 08             mov    0x8(%rax),%rdi
      18:   48 d3 e2                shl    %cl,%rdx
      1b:   48 21 f2                and    %rsi,%rdx
      1e:   48 2b 13                sub    (%rbx),%rdx
      21:   48 8b 30                mov    (%rax),%rsi
      24:   48 d3 ea                shr    %cl,%rdx
      27:   8b 4b 18                mov    0x18(%rbx),%ecx
            ...
    [    0.907095] RSP: 0018:ffffc900004a39a0 EFLAGS: 00010246
    [    0.907368] RAX: ffff8881043a0880 RBX: ffff888102953340 RCX: 0000000000000000
    [    0.907723] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
    [    0.908100] RBP: ffff888102952180 R08: 0000000000000000 R09: 0000000000000000
    [    0.908451] R10: ffff8881043a0000 R11: 0000000000000000 R12: ffff888102952000
    [    0.908804] R13: ffff888102952180 R14: ffff8881043a0ad8 R15: ffff8881043a0880
    [    0.909179] FS:  000000002a1a0380(0000) GS:ffff888196d8d000(0000) knlGS:0000000000000000
    [    0.909572] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    [    0.909857] CR2: 0000000000000000 CR3: 0000000102993002 CR4: 0000000000772ef0
    [    0.910247] PKRU: 55555554
    [    0.910391] Call Trace:
    [    0.910527]  <TASK>
    [    0.910638]  qfq_reset_qdisc (net/sched/sch_qfq.c:357 net/sched/sch_qfq.c:1485)
    [    0.910826]  qdisc_reset (include/linux/skbuff.h:2195 include/linux/skbuff.h:2501
    include/linux/skbuff.h:3424 include/linux/skbuff.h:3430 net/sched/sch_generic.c:1036)
    [    0.911040]  __qdisc_destroy (net/sched/sch_generic.c:1076)
    [    0.911236]  tc_new_tfilter (net/sched/cls_api.c:2447)
    [    0.911447]  rtnetlink_rcv_msg (net/core/rtnetlink.c:6958)
    [    0.911663]  ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6861)
    [    0.911894]  netlink_rcv_skb (net/netlink/af_netlink.c:2550)
    [    0.912100]  netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344)
    [    0.912296]  ? __alloc_skb (net/core/skbuff.c:706)
    [    0.912484]  netlink_sendmsg (net/netlink/af
    ---truncated---

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-2026-006745
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?9103350c");
  # https://lore.kernel.org/linux-cve-announce/2026012127-CVE-2026-22976-55e1@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?c73b768d");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2026-22976");
  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-2026-22976");

  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:"2026/01/21");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/04/08");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/04/08");

  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-5.10.0-27.5', '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}
    ]
  }
];

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');
}