Unity Linux 20.1050a Security Update: kernel (UTSA-2026-098960)

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

include('compat.inc');

if (description)
{
  script_id(340246);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/26");

  script_cve_id("CVE-2026-43456");

  script_name(english:"Unity Linux 20.1050a Security Update: kernel (UTSA-2026-098960)");

  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-2026-098960 advisory.

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

    bonding: fix type confusion in bond_setup_by_slave()

    kernel BUG at net/core/skbuff.c:2306!
    Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
    RIP: 0010:pskb_expand_head+0xa08/0xfe0 net/core/skbuff.c:2306
    RSP: 0018:ffffc90004aff760 EFLAGS: 00010293
    RAX: 0000000000000000 RBX: ffff88807e3c8780 RCX: ffffffff89593e0e
    RDX: ffff88807b7c4900 RSI: ffffffff89594747 RDI: ffff88807b7c4900
    RBP: 0000000000000820 R08: 0000000000000005 R09: 0000000000000000
    R10: 00000000961a63e0 R11: 0000000000000000 R12: ffff88807e3c8780
    R13: 00000000961a6560 R14: dffffc0000000000 R15: 00000000961a63e0
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 00007fe1a0ed8df0 CR3: 000000002d816000 CR4: 00000000003526f0
    Call Trace:
     <TASK>
     ipgre_header+0xdd/0x540 net/ipv4/ip_gre.c:900
     dev_hard_header include/linux/netdevice.h:3439 [inline]
     packet_snd net/packet/af_packet.c:3028 [inline]
     packet_sendmsg+0x3ae5/0x53c0 net/packet/af_packet.c:3108
     sock_sendmsg_nosec net/socket.c:727 [inline]
     __sock_sendmsg net/socket.c:742 [inline]
     ____sys_sendmsg+0xa54/0xc30 net/socket.c:2592
     ___sys_sendmsg+0x190/0x1e0 net/socket.c:2646
     __sys_sendmsg+0x170/0x220 net/socket.c:2678
     do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
     do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
     entry_SYSCALL_64_after_hwframe+0x77/0x7f
    RIP: 0033:0x7fe1a0e6c1a9

    When a non-Ethernet device (e.g. GRE tunnel) is enslaved to a bond,
    bond_setup_by_slave() directly copies the slave's header_ops to the
    bond device:

        bond_dev->header_ops = slave_dev->header_ops;

    This causes a type confusion when dev_hard_header() is later called
    on the bond device. Functions like ipgre_header(), ip6gre_header(),all use
    netdev_priv(dev) to access their device-specific private data. When
    called with the bond device, netdev_priv() returns the bond's private
    data (struct bonding) instead of the expected type (e.g. struct
    ip_tunnel), leading to garbage values being read and kernel crashes.

    Fix this by introducing bond_header_ops with wrapper functions that
    delegate to the active slave's header_ops using the slave's own
    device. This ensures netdev_priv() in the slave's header functions
    always receives the correct device.

    The fix is placed in the bonding driver rather than individual device
    drivers, as the root cause is bond blindly inheriting header_ops from
    the slave without considering that these callbacks expect a specific
    netdev_priv() layout.

    The type confusion can be observed by adding a printk in
    ipgre_header() and running the following commands:

        ip link add dummy0 type dummy
        ip addr add 10.0.0.1/24 dev dummy0
        ip link set dummy0 up
        ip link add gre1 type gre local 10.0.0.1
        ip link add bond1 type bond mode active-backup
        ip link set gre1 master bond1
        ip link set gre1 up
        ip link set bond1 up
        ip addr add fe80::1/64 dev bond1

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-2026-098960
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?18f60dd7");
  # https://lore.kernel.org/linux-cve-announce/2026050859-CVE-2026-43456-ae60@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?f194c788");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2026-43456");
  script_set_attribute(attribute:"solution", value:
"Update the affected kernel package.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:S/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:L/AC:L/PR:L/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-2026-43456");

  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:"2026/04/30");
  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');
}