Unity Linux 20.1050a Security Update: kernel (UTSA-2026-104615)

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

include('compat.inc');

if (description)
{
  script_id(339573);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/26");

  script_cve_id("CVE-2026-74267");

  script_name(english:"Unity Linux 20.1050a Security Update: kernel (UTSA-2026-104615)");

  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-2026-104615 advisory.

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

    net/sched: sch_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen

    Whenever codel drops packets during peek, it calls
    qdisc_tree_reduce_backlog. An issue arises because it calls
    qdisc_tree_reduce_backlog before it reincrements the qlen. If qlen drops
    to zero, but peek returns an skb, the parent's qlen_notify callback will
    be executed even though codel still has 1 packet on the queue and, thus,
    will mistakenly deactivate the parent's class causing issues like a wild
    memory access when qfq has codel as a child:

    [   36.339843][  T370] Oops: general protection fault, probably for non-canonical address
    0xfbd59c0000000024: 0000 [#1] SMP KASAN NOPTI
    [   36.340408][  T370] KASAN: maybe wild-memory-access in range [0xdead000000000120-0xdead000000000127]
    [   36.340737][  T370] CPU: 2 UID: 0 PID: 370 Comm: tc Not tainted 7.1.0-rc5-00287-g66e13b626592 #87
    PREEMPT(full)
    [   36.341113][  T370] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
    [   36.341357][  T370] RIP: 0010:qfq_deactivate_agg (include/linux/list.h:1029 (discriminator 2)
    include/linux/list.h:1043 (discriminator 2) net/sched/sch_qfq.c:1369 (discriminator 2)
    net/sched/sch_qfq.c:1395 (discriminator 2)) sch_qfq
    [   36.342221][  T370] RSP: 0018:ffff8881100ef370 EFLAGS: 00010216
    [   36.342422][  T370] RAX: 0000000000000000 RBX: ffff8881058a9568 RCX: dffffc0000000000
    [   36.342664][  T370] RDX: 1ffff11021064dc3 RSI: ffff888108326e00 RDI: dffffc0000000000
    [   36.342905][  T370] RBP: ffff8881058a8280 R08: dead000000000122 R09: 1bd5a00000000024
    [   36.343140][  T370] R10: fffffbfff2940329 R11: fffffbfff2940329 R12: 0000000000000000
    [   36.343383][  T370] R13: dead000000000100 R14: ffff8881058a9580 R15: ffff8881058a9578
    [   36.343631][  T370] FS:  00007fc04b0ca780(0000) GS:ffff888184fef000(0000) knlGS:0000000000000000
    [   36.343911][  T370] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    [   36.344116][  T370] CR2: 0000557c02c02000 CR3: 000000010e0ba000 CR4: 0000000000750ef0
    [   36.344359][  T370] PKRU: 55555554
    [   36.344481][  T370] Call Trace:
    ...
    [   36.345054][  T370] qfq_reset_qdisc (net/sched/sch_qfq.c:357 net/sched/sch_qfq.c:1487) sch_qfq
    [   36.345222][  T370]  qdisc_reset (net/sched/sch_generic.c:1057)
    [   36.345503][  T370]  __qdisc_destroy (net/sched/sch_generic.c:1096)
    [   36.345677][  T370]  qdisc_graft (net/sched/sch_api.c:1062 net/sched/sch_api.c:1053
    net/sched/sch_api.c:1159)
    [   36.346335][  T370]  tc_get_qdisc (net/sched/sch_api.c:1528 net/sched/sch_api.c:1556)

    Fix this by only calling qdisc_tree_reduce_backlog in peek after the
    qlen is restored.

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-2026-104615
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?e64a9a27");
  # https://lore.kernel.org/linux-cve-announce/2026081543-CVE-2026-74267-d460@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?d7241e5c");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2026-74267");
  script_set_attribute(attribute:"solution", value:
"Update the affected kernel package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/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:N/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-2026-74267");

  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:"2026/08/11");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/08/25");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/08/26");

  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:"^(20.1050a)([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'UOS Server 20.1050a', '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': '1050a',
    'pkgs': [
      {'reference':'kernel-5.10.0-27.18.uelc20', 'sp':'1050a', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-27.18.uelc20', 'sp':'1050a', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-27.18.uelc20', 'sp':'1050a', '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');
}