Unity Linux 20.1070a Security Update: kernel (UTSA-2026-006985)

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

include('compat.inc');

if (description)
{
  script_id(308296);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/04/21");

  script_cve_id("CVE-2023-53655");

  script_name(english:"Unity Linux 20.1070a Security Update: kernel (UTSA-2026-006985)");

  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-2026-006985 advisory.

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

    rcu: Avoid stack overflow due to __rcu_irq_enter_check_tick() being kprobe-ed

    Registering a kprobe on __rcu_irq_enter_check_tick() can cause kernel
    stack overflow as shown below. This issue can be reproduced by enabling
    CONFIG_NO_HZ_FULL and booting the kernel with argument nohz_full=,
    and then giving the following commands at the shell prompt:

      # cd /sys/kernel/tracing/
      # echo 'p:mp1 __rcu_irq_enter_check_tick' >> kprobe_events
      # echo 1 > events/kprobes/enable

    This commit therefore adds __rcu_irq_enter_check_tick() to the kprobes
    blacklist using NOKPROBE_SYMBOL().

    Insufficient stack space to handle exception!
    ESR: 0x00000000f2000004 -- BRK (AArch64)
    FAR: 0x0000ffffccf3e510
    Task stack:     [0xffff80000ad30000..0xffff80000ad38000]
    IRQ stack:      [0xffff800008050000..0xffff800008058000]
    Overflow stack: [0xffff089c36f9f310..0xffff089c36fa0310]
    CPU: 5 PID: 190 Comm: bash Not tainted 6.2.0-rc2-00320-g1f5abbd77e2c #19
    Hardware name: linux,dummy-virt (DT)
    pstate: 400003c5 (nZcv DAIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
    pc : __rcu_irq_enter_check_tick+0x0/0x1b8
    lr : ct_nmi_enter+0x11c/0x138
    sp : ffff80000ad30080
    x29: ffff80000ad30080 x28: ffff089c82e20000 x27: 0000000000000000
    x26: 0000000000000000 x25: ffff089c02a8d100 x24: 0000000000000000
    x23: 00000000400003c5 x22: 0000ffffccf3e510 x21: ffff089c36fae148
    x20: ffff80000ad30120 x19: ffffa8da8fcce148 x18: 0000000000000000
    x17: 0000000000000000 x16: 0000000000000000 x15: ffffa8da8e44ea6c
    x14: ffffa8da8e44e968 x13: ffffa8da8e03136c x12: 1fffe113804d6809
    x11: ffff6113804d6809 x10: 0000000000000a60 x9 : dfff800000000000
    x8 : ffff089c026b404f x7 : 00009eec7fb297f7 x6 : 0000000000000001
    x5 : ffff80000ad30120 x4 : dfff800000000000 x3 : ffffa8da8e3016f4
    x2 : 0000000000000003 x1 : 0000000000000000 x0 : 0000000000000000
    Kernel panic - not syncing: kernel stack overflow
    CPU: 5 PID: 190 Comm: bash Not tainted 6.2.0-rc2-00320-g1f5abbd77e2c #19
    Hardware name: linux,dummy-virt (DT)
    Call trace:
     dump_backtrace+0xf8/0x108
     show_stack+0x20/0x30
     dump_stack_lvl+0x68/0x84
     dump_stack+0x1c/0x38
     panic+0x214/0x404
     add_taint+0x0/0xf8
     panic_bad_stack+0x144/0x160
     handle_bad_stack+0x38/0x58
     __bad_stack+0x78/0x7c
     __rcu_irq_enter_check_tick+0x0/0x1b8
     arm64_enter_el1_dbg.isra.0+0x14/0x20
     el1_dbg+0x2c/0x90
     el1h_64_sync_handler+0xcc/0xe8
     el1h_64_sync+0x64/0x68
     __rcu_irq_enter_check_tick+0x0/0x1b8
     arm64_enter_el1_dbg.isra.0+0x14/0x20
     el1_dbg+0x2c/0x90
     el1h_64_sync_handler+0xcc/0xe8
     el1h_64_sync+0x64/0x68
     __rcu_irq_enter_check_tick+0x0/0x1b8
     arm64_enter_el1_dbg.isra.0+0x14/0x20
     el1_dbg+0x2c/0x90
     el1h_64_sync_handler+0xcc/0xe8
     el1h_64_sync+0x64/0x68
     __rcu_irq_enter_check_tick+0x0/0x1b8
     [...]
     el1_dbg+0x2c/0x90
     el1h_64_sync_handler+0xcc/0xe8
     el1h_64_sync+0x64/0x68
     __rcu_irq_enter_check_tick+0x0/0x1b8
     arm64_enter_el1_dbg.isra.0+0x14/0x20
     el1_dbg+0x2c/0x90
     el1h_64_sync_handler+0xcc/0xe8
     el1h_64_sync+0x64/0x68
     __rcu_irq_enter_check_tick+0x0/0x1b8
     arm64_enter_el1_dbg.isra.0+0x14/0x20
     el1_dbg+0x2c/0x90
     el1h_64_sync_handler+0xcc/0xe8
     el1h_64_sync+0x64/0x68
     __rcu_irq_enter_check_tick+0x0/0x1b8
     el1_interrupt+0x28/0x60
     el1h_64_irq_handler+0x18/0x28
     el1h_64_irq+0x64/0x68
     __ftrace_set_clr_event_nolock+0x98/0x198
     __ftrace_set_clr_event+0x58/0x80
     system_enable_write+0x144/0x178
     vfs_write+0x174/0x738
     ksys_write+0xd0/0x188
     __arm64_sys_write+0x4c/0x60
     invoke_syscall+0x64/0x180
     el0_svc_common.constprop.0+0x84/0x160
     do_el0_svc+0x48/0xe8
     el0_svc+0x34/0xd0
     el0t_64_sync_handler+0xb8/0xc0
     el0t_64_sync+0x190/0x194
    SMP: stopping secondary CPUs
    Kernel Offset: 0x28da86000000 from 0xffff800008000000
    PHYS_OFFSET: 0xfffff76600000000
    CPU features: 0x00000,01a00100,0000421b
    Memory Limit: none

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-2026-006985
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?4a845c55");
  # https://lore.kernel.org/linux-cve-announce/2025100701-CVE-2023-53655-d389@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?575ea251");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2023-53655");
  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-2023-53655");

  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:"2021/07/21");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/04/08");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/04/21");

  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-5.10.0-48', 'sp':'1070a', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-48', 'sp':'1070a', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-48', 'sp':'1070a', 'cpu':'loongarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-5.10.0-48', '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_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');
}