Unity Linux 20.1050a Security Update: kernel (UTSA-2026-098995)

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

include('compat.inc');

if (description)
{
  script_id(340449);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/26");

  script_cve_id("CVE-2025-38449");

  script_name(english:"Unity Linux 20.1050a Security Update: kernel (UTSA-2026-098995)");

  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-2026-098995 advisory.

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

    drm/gem: Acquire references on GEM handles for framebuffers

    A GEM handle can be released while the GEM buffer object is attached
    to a DRM framebuffer. This leads to the release of the dma-buf backing
    the buffer object, if any. [1] Trying to use the framebuffer in further
    mode-setting operations leads to a segmentation fault. Most easily
    happens with driver that use shadow planes for vmap-ing the dma-buf
    during a page flip. An example is shown below.

    [  156.791968] ------------[ cut here ]------------
    [  156.796830] WARNING: CPU: 2 PID: 2255 at drivers/dma-buf/dma-buf.c:1527 dma_buf_vmap+0x224/0x430
    [...]
    [  156.942028] RIP: 0010:dma_buf_vmap+0x224/0x430
    [  157.043420] Call Trace:
    [  157.045898]  <TASK>
    [  157.048030]  ? show_trace_log_lvl+0x1af/0x2c0
    [  157.052436]  ? show_trace_log_lvl+0x1af/0x2c0
    [  157.056836]  ? show_trace_log_lvl+0x1af/0x2c0
    [  157.061253]  ? drm_gem_shmem_vmap+0x74/0x710
    [  157.065567]  ? dma_buf_vmap+0x224/0x430
    [  157.069446]  ? __warn.cold+0x58/0xe4
    [  157.073061]  ? dma_buf_vmap+0x224/0x430
    [  157.077111]  ? report_bug+0x1dd/0x390
    [  157.080842]  ? handle_bug+0x5e/0xa0
    [  157.084389]  ? exc_invalid_op+0x14/0x50
    [  157.088291]  ? asm_exc_invalid_op+0x16/0x20
    [  157.092548]  ? dma_buf_vmap+0x224/0x430
    [  157.096663]  ? dma_resv_get_singleton+0x6d/0x230
    [  157.101341]  ? __pfx_dma_buf_vmap+0x10/0x10
    [  157.105588]  ? __pfx_dma_resv_get_singleton+0x10/0x10
    [  157.110697]  drm_gem_shmem_vmap+0x74/0x710
    [  157.114866]  drm_gem_vmap+0xa9/0x1b0
    [  157.118763]  drm_gem_vmap_unlocked+0x46/0xa0
    [  157.123086]  drm_gem_fb_vmap+0xab/0x300
    [  157.126979]  drm_atomic_helper_prepare_planes.part.0+0x487/0xb10
    [  157.133032]  ? lockdep_init_map_type+0x19d/0x880
    [  157.137701]  drm_atomic_helper_commit+0x13d/0x2e0
    [  157.142671]  ? drm_atomic_nonblocking_commit+0xa0/0x180
    [  157.147988]  drm_mode_atomic_ioctl+0x766/0xe40
    [...]
    [  157.346424] ---[ end trace 0000000000000000 ]---

    Acquiring GEM handles for the framebuffer's GEM buffer objects prevents
    this from happening. The framebuffer's cleanup later puts the handle
    references.

    Commit 1a148af06000 (drm/gem-shmem: Use dma_buf from GEM object
    instance) triggers the segmentation fault easily by using the dma-buf
    field more widely. The underlying issue with reference counting has
    been present before.

    v2:
    - acquire the handle instead of the BO (Christian)
    - fix comment style (Christian)
    - drop the Fixes tag (Christian)
    - rename err_ gotos
    - add missing Link tag

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-2026-098995
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?9c4d3750");
  # https://lore.kernel.org/linux-cve-announce/2025072504-CVE-2025-38449-cbf0@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?6867b9f4");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2025-38449");
  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-2025-38449");

  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:"2025/02/12");
  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');
}