Unity Linux 20.1050e Security Update: kernel (UTSA-2026-102073)

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

include('compat.inc');

if (description)
{
  script_id(338588);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/21");

  script_cve_id("CVE-2025-40205");

  script_name(english:"Unity Linux 20.1050e Security Update: kernel (UTSA-2026-102073)");

  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-2026-102073 advisory.

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

    btrfs: avoid potential out-of-bounds in btrfs_encode_fh()

    The function btrfs_encode_fh() does not properly account for the three
    cases it handles.

    Before writing to the file handle (fh), the function only returns to the
    user BTRFS_FID_SIZE_NON_CONNECTABLE (5 dwords, 20 bytes) or
    BTRFS_FID_SIZE_CONNECTABLE (8 dwords, 32 bytes).

    However, when a parent exists and the root ID of the parent and the
    inode are different, the function writes BTRFS_FID_SIZE_CONNECTABLE_ROOT
    (10 dwords, 40 bytes).

    If *max_len is not large enough, this write goes out of bounds because
    BTRFS_FID_SIZE_CONNECTABLE_ROOT is greater than
    BTRFS_FID_SIZE_CONNECTABLE originally returned.

    This results in an 8-byte out-of-bounds write at
    fid->parent_root_objectid = parent_root_id.

    A previous attempt to fix this issue was made but was lost.

    https://lore.kernel.org/all/[email protected]/

    Although this issue does not seem to be easily triggerable, it is a
    potential memory corruption bug that should be fixed. This patch
    resolves the issue by ensuring the function returns the appropriate size
    for all three cases and validates that *max_len is large enough before
    writing any data.

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-2026-102073
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?0099c6b3");
  # https://git.kernel.org/stable/c/0276c8582488022f057b4cec21975a5edf079f47
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?3d0f39d8");
  # https://git.kernel.org/stable/c/361d67276eb8ec6be8f27f4ad6c6090459438fee
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?bda9ea08");
  # https://git.kernel.org/stable/c/43143776b0a7604d873d1a6f3e552a00aa930224
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?2852d45d");
  # https://git.kernel.org/stable/c/60de2f55d2aca53e81b4ef2a67d7cc9e1eb677db
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?4cf09992");
  # https://git.kernel.org/stable/c/742b44342204e5dfe3926433823623c1a0c581df
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?90ce9075");
  # https://git.kernel.org/stable/c/d3a9a8e1275eb9b87f006b5562a287aea3f6885f
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?c68ee792");
  # https://git.kernel.org/stable/c/d91f6626133698362bba08fbc04bd72c466806d3
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?a9637a1d");
  # https://git.kernel.org/stable/c/dff4f9ff5d7f289e4545cc936362e01ed3252742
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?ab39e36f");
  # https://lore.kernel.org/linux-cve-announce/2025111247-CVE-2025-40205-ad43@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?6964cf34");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2025-40205");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2025-40205");
  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-2025-40205");

  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:"2025/10/23");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/08/17");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/08/21");

  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:"^(20.1050e)([^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_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');
}