Unity Linux 20.1050a Security Update: kernel (UTSA-2026-098941)

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

include('compat.inc');

if (description)
{
  script_id(340209);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/28");

  script_cve_id("CVE-2026-23011");

  script_name(english:"Unity Linux 20.1050a Security Update: kernel (UTSA-2026-098941)");

  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-2026-098941 advisory.

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

    ipv4: ip_gre: make ipgre_header() robust

    Analog to commit db5b4e39c4e6 (ip6_gre: make ip6gre_header() robust)

    Over the years, syzbot found many ways to crash the kernel
    in ipgre_header() [1].

    This involves team or bonding drivers ability to dynamically
    change their dev->needed_headroom and/or dev->hard_header_len

    In this particular crash mld_newpack() allocated an skb
    with a too small reserve/headroom, and by the time mld_sendpack()
    was called, syzbot managed to attach an ipgre device.

    [1]
    skbuff: skb_under_panic: text:ffffffff89ea3cb7 len:2030915468 put:2030915372 head:ffff888058b43000
    data:ffff887fdfa6e194 tail:0x120 end:0x6c0 dev:team0
     kernel BUG at net/core/skbuff.c:213 !
    Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
    CPU: 1 UID: 0 PID: 1322 Comm: kworker/1:9 Not tainted syzkaller #0 PREEMPT(full)
    Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
    Workqueue: mld mld_ifc_work
     RIP: 0010:skb_panic+0x157/0x160 net/core/skbuff.c:213
    Call Trace:
     <TASK>
      skb_under_panic net/core/skbuff.c:223 [inline]
      skb_push+0xc3/0xe0 net/core/skbuff.c:2641
      ipgre_header+0x67/0x290 net/ipv4/ip_gre.c:897
      dev_hard_header include/linux/netdevice.h:3436 [inline]
      neigh_connected_output+0x286/0x460 net/core/neighbour.c:1618
      NF_HOOK_COND include/linux/netfilter.h:307 [inline]
      ip6_output+0x340/0x550 net/ipv6/ip6_output.c:247
      NF_HOOK+0x9e/0x380 include/linux/netfilter.h:318
      mld_sendpack+0x8d4/0xe60 net/ipv6/mcast.c:1855
      mld_send_cr net/ipv6/mcast.c:2154 [inline]
      mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693
      process_one_work kernel/workqueue.c:3257 [inline]
      process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
      worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
      kthread+0x711/0x8a0 kernel/kthread.c:463
      ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
      ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

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-2026-098941
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?1c94d911");
  # https://lore.kernel.org/linux-cve-announce/2026012538-CVE-2026-23011-d4fd@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?54dd9c37");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2026-23011");
  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-2026-23011");

  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:"2026/01/25");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/08/10");
  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 && 'loongarch64' >!< cpu && 'x86_64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'UOS Server', cpu);


var constraints = [
  {
    'release': '20',
    'sp': '1050a',
    'pkgs': [
      {'reference':'kernel-4.19.0-91.82.132.24.uelc20', 'sp':'1050a', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.0-91.82.132.24.uelc20', 'sp':'1050a', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.0-91.82.132.24.uelc20', 'sp':'1050a', 'cpu':'loongarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.0-91.82.132.24.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');
}