Unity Linux 20.1050e Security Update: kernel (UTSA-2026-102135)

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

include('compat.inc');

if (description)
{
  script_id(337291);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/18");

  script_cve_id("CVE-2025-68206");

  script_name(english:"Unity Linux 20.1050e Security Update: kernel (UTSA-2026-102135)");

  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-2026-102135 advisory.

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

    netfilter: nft_ct: add seqadj extension for natted connections

    Sequence adjustment may be required for FTP traffic with PASV/EPSV modes.
    due to need to re-write packet payload (IP, port) on the ftp control
    connection. This can require changes to the TCP length and expected
    seq / ack_seq.

    The easiest way to reproduce this issue is with PASV mode.
    Example ruleset:
    table inet ftp_nat {
            ct helper ftp_helper {
                    type ftp protocol tcp
                    l3proto inet
            }

            chain prerouting {
                    type filter hook prerouting priority 0; policy accept;
                    tcp dport 21 ct state new ct helper set ftp_helper
            }
    }
    table ip nat {
            chain prerouting {
                    type nat hook prerouting priority -100; policy accept;
                    tcp dport 21 dnat ip prefix to ip daddr map {
                            192.168.100.1 : 192.168.13.2/32 }
            }

            chain postrouting {
                    type nat hook postrouting priority 100 ; policy accept;
                    tcp sport 21 snat ip prefix to ip saddr map {
                            192.168.13.2 : 192.168.100.1/32 }
            }
    }

    Note that the ftp helper gets assigned *after* the dnat setup.

    The inverse (nat after helper assign) is handled by an existing
    check in nf_nat_setup_info() and will not show the problem.

    Topoloy:

     +-------------------+     +----------------------------------+
     | FTP: 192.168.13.2 | <-> | NAT: 192.168.13.3, 192.168.100.1 |
     +-------------------+     +----------------------------------+
                                          |
                             +-----------------------+
                             | Client: 192.168.100.2 |
                             +-----------------------+

    ftp nat changes do not work as expected in this case:
    Connected to 192.168.100.1.
    [..]
    ftp> epsv
    EPSV/EPRT on IPv4 off.
    ftp> ls
    227 Entering passive mode (192,168,100,1,209,129).
    421 Service not available, remote server has closed connection.

    Kernel logs:
    Missing nfct_seqadj_ext_add() setup call
    WARNING: CPU: 1 PID: 0 at net/netfilter/nf_conntrack_seqadj.c:41
    [..]
     __nf_nat_mangle_tcp_packet+0x100/0x160 [nf_nat]
     nf_nat_ftp+0x142/0x280 [nf_nat_ftp]
     help+0x4d1/0x880 [nf_conntrack_ftp]
     nf_confirm+0x122/0x2e0 [nf_conntrack]
     nf_hook_slow+0x3c/0xb0
     ..

    Fix this by adding the required extension when a conntrack helper is assigned
    to a connection that has a nat binding.

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-2026-102135
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?05ba476c");
  script_set_attribute(attribute:"see_also", value:"https://atomgit.com/src-openeuler/kernel/issues/11571");
  # https://lore.kernel.org/linux-cve-announce/2025121632-CVE-2025-68206-47ba@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?1236d439");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2025-68206");
  script_set_attribute(attribute:"solution", value:
"Update the affected kernel package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/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:N/AC:L/PR:N/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-2025-68206");

  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:"2025/12/16");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/08/17");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/08/18");

  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:"^20.1050e([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'UOS Server 20.1050e', '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': '1050e',
    'pkgs': [
      {'reference':'kernel-4.19.90-2211.5.0.0178.67.uel20', 'sp':'1050e', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2211.5.0.0178.67.uel20', 'sp':'1050e', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.90-2211.5.0.0178.67.uel20', 'sp':'1050e', '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');
}