Unity Linux 20.1070a Security Update: kernel (UTSA-2026-146309)

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

include('compat.inc');

if (description)
{
  script_id(372563);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/27");

  script_cve_id("CVE-2026-74691");

  script_name(english:"Unity Linux 20.1070a Security Update: kernel (UTSA-2026-146309)");

  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-2026-146309 advisory.

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

    net: thunderbolt: Tear down DMA paths before stopping the rings

    tbnet_tear_down() stops both rings and frees their frame buffers before
    calling tb_xdomain_disable_paths().  tb_ring_stop() zeroes the ring's
    descriptor base and tbnet_free_buffers() unmaps and frees the pages the
    frames sit in, so by the time __tb_path_deactivate_hop() polls the hop's
    'pending' bit, anything still in flight has nowhere to drain to.

    The teardown sequence has been in this order since the driver was added.
    The setup path has not: commit ff7cd07f3064 (net: thunderbolt: Enable
    DMA paths only after rings are enabled) moved the path enable to the end
    of tbnet_connected_work() and documented why:

            /* Both logins successful so enable the rings, high-speed DMA
             * paths and start the network device queue.
             *
             * Note we enable the DMA paths last to make sure we have primed
             * the Rx ring before any incoming packets are allowed to
             * arrive.
             */

    Teardown was never updated to match, so the rings and the paths now come
    down in the same order they go up instead of in reverse.

    On an ASMedia ASM4242 host router the 'pending' bit then never clears:
    every teardown burns the full 500 ms timeout and
    __tb_path_deactivate_hop() returns -ETIMEDOUT.  Raising the timeout to
    5 s does not help, so the hop is not slow to drain, it never drains
    at all.

    The failure is invisible above the thunderbolt core.
    __tb_path_deactivate_hops() is void and only calls tb_port_warn();
    tb_path_deactivate(), tb_tunnel_deactivate() and
    __tb_disconnect_xdomain_paths() are void as well, and
    tb_disconnect_xdomain_paths() ends in an unconditional return 0.  So
    tb_xdomain_disable_paths() reports success and the netdev_warn() below
    it never fires.  Repeated teardowns eventually take the XDomain control
    channel down, after which the peer node is gone and only a power cycle
    brings the controller back.

    Deactivating the paths first fixes it.  Measured with kretprobes on a
    stock v6.17 tree with no other patches applied, on a link that was up
    and had just carried traffic:

      before: __tb_path_deactivate_hop() returns 0 for the first hop, then
              -ETIMEDOUT for the second 500335 us later
      after:  0 for both, 525 us apart

    Alternating the two orderings ABBA over three load levels, four
    teardowns per arm: every teardown failed before the change (21 of 21
    that ran), none failed after (0 of 24).  The before arms ran short
    because the link died partway through.  The same split shows up when
    the interface is enslaved to a bond instead of just brought down, which
    is how I ran into this in the first place.  Throughput and latency after
    the change are unchanged.

    Hosts whose routers drain the hop despite the stale descriptor base see
    no functional difference, since the paths end up deactivated either way.

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-2026-146309
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?c66f90d7");
  # https://lore.kernel.org/linux-cve-announce/2026082233-CVE-2026-74691-08a4@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?2a93f3bd");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2026-74691");
  script_set_attribute(attribute:"solution", value:
"Update the affected kernel package.");
  script_set_cvss_base_vector("CVSS2#AV:A/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:A/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-2026-74691");

  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:"2026/08/22");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/10/28");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/27");

  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-4.19.0-91.82.190.028.uelc20', 'sp':'1070a', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.0-91.82.190.028.uelc20', 'sp':'1070a', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.0-91.82.190.028.uelc20', 'sp':'1070a', 'cpu':'loongarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.0-91.82.190.028.uelc20', '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_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');
}