Unity Linux 20.1050a Security Update: kernel (UTSA-2026-098849)

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

include('compat.inc');

if (description)
{
  script_id(340406);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/26");

  script_cve_id("CVE-2025-37738");

  script_name(english:"Unity Linux 20.1050a Security Update: kernel (UTSA-2026-098849)");

  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-2026-098849 advisory.

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

    ext4: ignore xattrs past end

    Once inside 'ext4_xattr_inode_dec_ref_all' we should
    ignore xattrs entries past the 'end' entry.

    This fixes the following KASAN reported issue:

    ==================================================================
    BUG: KASAN: slab-use-after-free in ext4_xattr_inode_dec_ref_all+0xb8c/0xe90
    Read of size 4 at addr ffff888012c120c4 by task repro/2065

    CPU: 1 UID: 0 PID: 2065 Comm: repro Not tainted 6.13.0-rc2+ #11
    Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org
    04/01/2014
    Call Trace:
     <TASK>
     dump_stack_lvl+0x1fd/0x300
     ? tcp_gro_dev_warn+0x260/0x260
     ? _printk+0xc0/0x100
     ? read_lock_is_recursive+0x10/0x10
     ? irq_work_queue+0x72/0xf0
     ? __virt_addr_valid+0x17b/0x4b0
     print_address_description+0x78/0x390
     print_report+0x107/0x1f0
     ? __virt_addr_valid+0x17b/0x4b0
     ? __virt_addr_valid+0x3ff/0x4b0
     ? __phys_addr+0xb5/0x160
     ? ext4_xattr_inode_dec_ref_all+0xb8c/0xe90
     kasan_report+0xcc/0x100
     ? ext4_xattr_inode_dec_ref_all+0xb8c/0xe90
     ext4_xattr_inode_dec_ref_all+0xb8c/0xe90
     ? ext4_xattr_delete_inode+0xd30/0xd30
     ? __ext4_journal_ensure_credits+0x5f0/0x5f0
     ? __ext4_journal_ensure_credits+0x2b/0x5f0
     ? inode_update_timestamps+0x410/0x410
     ext4_xattr_delete_inode+0xb64/0xd30
     ? ext4_truncate+0xb70/0xdc0
     ? ext4_expand_extra_isize_ea+0x1d20/0x1d20
     ? __ext4_mark_inode_dirty+0x670/0x670
     ? ext4_journal_check_start+0x16f/0x240
     ? ext4_inode_is_fast_symlink+0x2f2/0x3a0
     ext4_evict_inode+0xc8c/0xff0
     ? ext4_inode_is_fast_symlink+0x3a0/0x3a0
     ? do_raw_spin_unlock+0x53/0x8a0
     ? ext4_inode_is_fast_symlink+0x3a0/0x3a0
     evict+0x4ac/0x950
     ? proc_nr_inodes+0x310/0x310
     ? trace_ext4_drop_inode+0xa2/0x220
     ? _raw_spin_unlock+0x1a/0x30
     ? iput+0x4cb/0x7e0
     do_unlinkat+0x495/0x7c0
     ? try_break_deleg+0x120/0x120
     ? 0xffffffff81000000
     ? __check_object_size+0x15a/0x210
     ? strncpy_from_user+0x13e/0x250
     ? getname_flags+0x1dc/0x530
     __x64_sys_unlinkat+0xc8/0xf0
     do_syscall_64+0x65/0x110
     entry_SYSCALL_64_after_hwframe+0x67/0x6f
    RIP: 0033:0x434ffd
    Code: 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d
    89 c8 8
    RSP: 002b:00007ffc50fa7b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000107
    RAX: ffffffffffffffda RBX: 00007ffc50fa7e18 RCX: 0000000000434ffd
    RDX: 0000000000000000 RSI: 0000000020000240 RDI: 0000000000000005
    RBP: 00007ffc50fa7be0 R08: 0000000000000000 R09: 0000000000000000
    R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
    R13: 00007ffc50fa7e08 R14: 00000000004bbf30 R15: 0000000000000001
     </TASK>

    The buggy address belongs to the object at ffff888012c12000
     which belongs to the cache filp of size 360
    The buggy address is located 196 bytes inside of
     freed 360-byte region [ffff888012c12000, ffff888012c12168)

    The buggy address belongs to the physical page:
    page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12c12
    head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
    flags: 0x40(head|node=0|zone=0)
    page_type: f5(slab)
    raw: 0000000000000040 ffff888000ad7640 ffffea0000497a00 dead000000000004
    raw: 0000000000000000 0000000000100010 00000001f5000000 0000000000000000
    head: 0000000000000040 ffff888000ad7640 ffffea0000497a00 dead000000000004
    head: 0000000000000000 0000000000100010 00000001f5000000 0000000000000000
    head: 0000000000000001 ffffea00004b0481 ffffffffffffffff 0000000000000000
    head: 0000000000000002 0000000000000000 00000000ffffffff 0000000000000000
    page dumped because: kasan: bad access detected

    Memory state around the buggy address:
     ffff888012c11f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
     ffff888012c12000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
    > ffff888012c12080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                               ^
     ffff888012c12100: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc
     ffff888012c12180: fc fc fc fc fc fc fc fc fc
    ---truncated---

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-2026-098849
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?e97a68cc");
  # https://lore.kernel.org/linux-cve-announce/2025050132-CVE-2025-37738-deb1@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?57a0ac0e");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2025-37738");
  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-2025-37738");

  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:"2025/05/01");
  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');
}