Unity Linux 20.1050a Security Update: kernel (UTSA-2026-100768)

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

include('compat.inc');

if (description)
{
  script_id(336903);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/17");

  script_cve_id("CVE-2026-46250");

  script_name(english:"Unity Linux 20.1050a Security Update: kernel (UTSA-2026-100768)");

  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-2026-100768 advisory.

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

    MIPS: Work around LLVM bug when gp is used as global register variable

    On MIPS, __current_thread_info is defined as global register variable
    locating in $gp, and is simply assigned with new address during kernel
    relocation.

    This however is broken with LLVM, which always restores $gp if it finds
    $gp is clobbered in any form, including when intentionally through a
    global register variable. This is against GCC's documentation[1], which
    requires a callee-saved register used as global register variable not to
    be restored if it's clobbered.

    As a result, $gp will continue to point to the unrelocated kernel after
    the epilog of relocate_kernel(), leading to an early crash in init_idle,

    [    0.000000] CPU 0 Unable to handle kernel paging request at virtual address 0000000000000000, epc ==
    ffffffff81afada8, ra == ffffffff81afad90
    [    0.000000] Oops[#1]:
    [    0.000000] CPU: 0 UID: 0 PID: 0 Comm: swapper Tainted: G        W
    6.19.0-rc5-00262-gd3eeb99bbc99-dirty #188 VOLUNTARY
    [    0.000000] Tainted: [W]=WARN
    [    0.000000] Hardware name: loongson,loongson64v-4core-virtio
    [    0.000000] $ 0   : 0000000000000000 0000000000000000 0000000000000001 0000000000000000
    [    0.000000] $ 4   : ffffffff80b80ec0 ffffffff80b53d48 0000000000000000 00000000000f4240
    [    0.000000] $ 8   : 0000000000000100 ffffffff81d82f80 ffffffff81d82f80 0000000000000001
    [    0.000000] $12   : 0000000000000000 ffffffff81776f58 00000000000005da 0000000000000002
    [    0.000000] $16   : ffffffff80b80e40 0000000000000000 ffffffff80b81614 9800000005dfbe80
    [    0.000000] $20   : 00000000540000e0 ffffffff81980000 0000000000000000 ffffffff80f81c80
    [    0.000000] $24   : 0000000000000a26 ffffffff8114fb90
    [    0.000000] $28   : ffffffff80b50000 ffffffff80b53d40 0000000000000000 ffffffff81afad90
    [    0.000000] Hi    : 0000000000000000
    [    0.000000] Lo    : 0000000000000000
    [    0.000000] epc   : ffffffff81afada8 init_idle+0x130/0x270
    [    0.000000] ra    : ffffffff81afad90 init_idle+0x118/0x270
    [    0.000000] Status: 540000e2 KX SX UX KERNEL EXL
    [    0.000000] Cause : 00000008 (ExcCode 02)
    [    0.000000] BadVA : 0000000000000000
    [    0.000000] PrId  : 00006305 (ICT Loongson-3)
    [    0.000000] Process swapper (pid: 0, threadinfo=(____ptrval____), task=(____ptrval____),
    tls=0000000000000000)
    [    0.000000] Stack : 9800000005dfbf00 ffffffff8178e950 0000000000000000 0000000000000000
    [    0.000000]         0000000000000000 ffffffff81970000 000000000000003f ffffffff810a6528
    [    0.000000]         0000000000000001 9800000005dfbe80 9800000005dfbf00 ffffffff81980000
    [    0.000000]         ffffffff810a6450 ffffffff81afb6c0 0000000000000000 ffffffff810a2258
    [    0.000000]         ffffffff81d82ec8 ffffffff8198d010 ffffffff81b67e80 ffffffff8197dd98
    [    0.000000]         ffffffff81d81c80 ffffffff81930000 0000000000000040 0000000000000000
    [    0.000000]         0000000000000000 0000000000000000 0000000000000000 0000000000000000
    [    0.000000]         0000000000000000 000000000000009e ffffffff9fc01000 0000000000000000
    [    0.000000]         0000000000000000 0000000000000000 0000000000000000 0000000000000000
    [    0.000000]         0000000000000000 ffffffff81ae86dc ffffffff81b3c741 0000000000000002
    [    0.000000]         ...
    [    0.000000] Call Trace:
    [    0.000000] [<ffffffff81afada8>] init_idle+0x130/0x270
    [    0.000000] [<ffffffff81afb6c0>] sched_init+0x5c8/0x6c0
    [    0.000000] [<ffffffff81ae86dc>] start_kernel+0x27c/0x7a8

    This bug has been reported to LLVM[2] and affects version from (at
    least) 18 to 21. Let's work around this by using inline assembly to
    assign $gp before a fix is widely available.

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-2026-100768
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?3313636e");
  # https://lore.kernel.org/linux-cve-announce/2026060334-CVE-2026-46250-736e@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?7b9607f5");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2026-46250");
  script_set_attribute(attribute:"solution", value:
"Update the affected kernel package.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:P/I:P/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:N/UI:N/S:U/C:L/I:L/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-2026-46250");

  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:"2026/05/07");
  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:"^20.1050a([^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_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');
}