KB5073723: Windows 10 version 1809 / Windows Server 2019 Security Update (January 2026)

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

#
# The descriptive text and package checks in this plugin were
# extracted from the Microsoft Security Updates API. The text
# itself is copyright (C) Microsoft Corporation.
##

include('compat.inc');

if (description)
{
  script_id(283470);
  script_version("1.5");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/02/24");

  script_cve_id(
    "CVE-2023-31096",
    "CVE-2024-55414",
    "CVE-2026-0386",
    "CVE-2026-20804",
    "CVE-2026-20805",
    "CVE-2026-20809",
    "CVE-2026-20810",
    "CVE-2026-20812",
    "CVE-2026-20814",
    "CVE-2026-20816",
    "CVE-2026-20818",
    "CVE-2026-20820",
    "CVE-2026-20821",
    "CVE-2026-20822",
    "CVE-2026-20823",
    "CVE-2026-20824",
    "CVE-2026-20825",
    "CVE-2026-20826",
    "CVE-2026-20827",
    "CVE-2026-20828",
    "CVE-2026-20829",
    "CVE-2026-20831",
    "CVE-2026-20832",
    "CVE-2026-20833",
    "CVE-2026-20834",
    "CVE-2026-20836",
    "CVE-2026-20837",
    "CVE-2026-20839",
    "CVE-2026-20840",
    "CVE-2026-20843",
    "CVE-2026-20844",
    "CVE-2026-20847",
    "CVE-2026-20848",
    "CVE-2026-20849",
    "CVE-2026-20852",
    "CVE-2026-20853",
    "CVE-2026-20856",
    "CVE-2026-20857",
    "CVE-2026-20858",
    "CVE-2026-20860",
    "CVE-2026-20861",
    "CVE-2026-20862",
    "CVE-2026-20864",
    "CVE-2026-20865",
    "CVE-2026-20866",
    "CVE-2026-20867",
    "CVE-2026-20868",
    "CVE-2026-20869",
    "CVE-2026-20872",
    "CVE-2026-20873",
    "CVE-2026-20874",
    "CVE-2026-20875",
    "CVE-2026-20877",
    "CVE-2026-20918",
    "CVE-2026-20919",
    "CVE-2026-20921",
    "CVE-2026-20922",
    "CVE-2026-20923",
    "CVE-2026-20924",
    "CVE-2026-20925",
    "CVE-2026-20926",
    "CVE-2026-20927",
    "CVE-2026-20929",
    "CVE-2026-20931",
    "CVE-2026-20932",
    "CVE-2026-20934",
    "CVE-2026-20936",
    "CVE-2026-20937",
    "CVE-2026-20939",
    "CVE-2026-20940",
    "CVE-2026-20962",
    "CVE-2026-21265"
  );
  script_xref(name:"MSKB", value:"5073723");
  script_xref(name:"MSFT", value:"MS26-5073723");
  script_xref(name:"CISA-KNOWN-EXPLOITED", value:"2026/02/03");
  script_xref(name:"IAVA", value:"2026-A-0038");
  script_xref(name:"IAVA", value:"2026-A-0040-S");

  script_name(english:"KB5073723: Windows 10 version 1809 / Windows Server 2019 Security Update (January 2026)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Windows host is affected by multiple vulnerabilities.");
  script_set_attribute(attribute:"description", value:
"The remote Windows host is missing security update 5073723. It is, therefore, affected by multiple vulnerabilities

  - Untrusted pointer dereference in Windows Cloud Files Mini Filter Driver allows an authorized attacker to
    elevate privileges locally. (CVE-2026-20857)

  - An issue was discovered in Broadcom) LSI PCI-SV92EX Soft Modem Kernel Driver through 2.2.100.1 (aka
    AGRSM64.sys). There is Local Privilege Escalation to SYSTEM via a Stack Overflow in RTLCopyMemory (IOCTL
    0x1b2150). An attacker can exploit this to elevate privileges from a medium-integrity process to SYSTEM.
    This can also be used to bypass kernel-level protections such as AV or PPL, because exploit code runs with
    high-integrity privileges and can be used in coordinated BYOVD (bring your own vulnerable driver)
    ransomware campaigns. (CVE-2023-31096)

  - Windows Remote Procedure Call Interface Definition Language (IDL) Elevation of Privilege Vulnerability
    (CVE-2026-20832)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"https://support.microsoft.com/help/5073723");
  script_set_attribute(attribute:"solution", value:
"Apply Security Update 5073723");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:H/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:H/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-20868");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2023-31096");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"exploited_by_malware", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2023/10/10");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/01/13");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/01/13");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:microsoft:windows_10_1809");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:microsoft:windows_server_2019");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Windows : Microsoft Bulletins");

  script_copyright(english:"This script is Copyright (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("smb_check_rollup.nasl", "smb_hotfixes.nasl", "ms_bulletin_checks_possible.nasl");
  script_require_keys("SMB/MS_Bulletin_Checks/Possible");
  script_require_ports(139, 445, "Host/patch_management_checks");

  exit(0);
}

include('smb_func.inc');
include('smb_hotfixes.inc');
include('smb_hotfixes_fcheck.inc');
include('smb_reg_query.inc');

get_kb_item_or_exit('SMB/MS_Bulletin_Checks/Possible');

var bulletin = 'MS26-01';
var kbs = make_list(
  '5073723'
);

if (get_kb_item('Host/patch_management_checks')) hotfix_check_3rd_party(bulletin:bulletin, kbs:kbs, severity:SECURITY_HOLE);

get_kb_item_or_exit('SMB/Registry/Enumerated');
get_kb_item_or_exit('SMB/WindowsVersion', exit_code:1);

if (hotfix_check_sp_range(win10:'0') <= 0) audit(AUDIT_OS_SP_NOT_VULN);

var share = hotfix_get_systemdrive(as_share:TRUE, exit_on_fail:TRUE);
if (!is_accessible_share(share:share)) audit(AUDIT_SHARE_FAIL, share);

if (
  smb_check_rollup(os:'10',
                   os_build:17763,
                   rollup_date:'01_2026',
                   bulletin:bulletin,
                   rollup_kb_list:[5073723])
)
{
  replace_kb_item(name:'SMB/Missing/'+bulletin, value:TRUE);
  hotfix_security_hole();
  hotfix_check_fversion_end();
  exit(0);
}
else
{
  hotfix_check_fversion_end();
  audit(AUDIT_HOST_NOT, hotfix_get_audit_report());
}