KB5121000: Windows 11 Version 26H1 Security Update (August 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(334603);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/11");

  script_cve_id(
    "CVE-2026-49179",
    "CVE-2026-50472",
    "CVE-2026-54113",
    "CVE-2026-54984",
    "CVE-2026-56179",
    "CVE-2026-59122",
    "CVE-2026-59125",
    "CVE-2026-59126",
    "CVE-2026-59127",
    "CVE-2026-59128",
    "CVE-2026-59130",
    "CVE-2026-59131",
    "CVE-2026-59132",
    "CVE-2026-59134",
    "CVE-2026-59135",
    "CVE-2026-59136",
    "CVE-2026-59137",
    "CVE-2026-59138",
    "CVE-2026-61345",
    "CVE-2026-61346",
    "CVE-2026-61347",
    "CVE-2026-61348",
    "CVE-2026-61349",
    "CVE-2026-61350",
    "CVE-2026-61352",
    "CVE-2026-61353",
    "CVE-2026-61355",
    "CVE-2026-61356",
    "CVE-2026-61357",
    "CVE-2026-61358",
    "CVE-2026-61359",
    "CVE-2026-61360",
    "CVE-2026-61361",
    "CVE-2026-61363",
    "CVE-2026-61364",
    "CVE-2026-61365",
    "CVE-2026-61366",
    "CVE-2026-61367",
    "CVE-2026-61368",
    "CVE-2026-61918",
    "CVE-2026-61920",
    "CVE-2026-61921",
    "CVE-2026-61923",
    "CVE-2026-61924",
    "CVE-2026-61925",
    "CVE-2026-61926",
    "CVE-2026-61927",
    "CVE-2026-61928",
    "CVE-2026-61929",
    "CVE-2026-61930",
    "CVE-2026-61933",
    "CVE-2026-61934",
    "CVE-2026-61936",
    "CVE-2026-61937",
    "CVE-2026-61938",
    "CVE-2026-61939",
    "CVE-2026-62688",
    "CVE-2026-62690",
    "CVE-2026-62692",
    "CVE-2026-62693",
    "CVE-2026-62695",
    "CVE-2026-62696",
    "CVE-2026-62698",
    "CVE-2026-62699",
    "CVE-2026-62700",
    "CVE-2026-62701",
    "CVE-2026-62702",
    "CVE-2026-62703",
    "CVE-2026-62705",
    "CVE-2026-62707",
    "CVE-2026-62708",
    "CVE-2026-62709",
    "CVE-2026-62710",
    "CVE-2026-62711",
    "CVE-2026-62712",
    "CVE-2026-62713",
    "CVE-2026-62717",
    "CVE-2026-62719",
    "CVE-2026-62721",
    "CVE-2026-62722",
    "CVE-2026-62723",
    "CVE-2026-62724",
    "CVE-2026-62725",
    "CVE-2026-62726",
    "CVE-2026-62728",
    "CVE-2026-62729",
    "CVE-2026-62730",
    "CVE-2026-62732",
    "CVE-2026-62733",
    "CVE-2026-62734",
    "CVE-2026-62735",
    "CVE-2026-62736",
    "CVE-2026-62737",
    "CVE-2026-62738",
    "CVE-2026-62739",
    "CVE-2026-62740",
    "CVE-2026-62741",
    "CVE-2026-62743",
    "CVE-2026-62746",
    "CVE-2026-62747",
    "CVE-2026-62748",
    "CVE-2026-62749",
    "CVE-2026-62750",
    "CVE-2026-62751",
    "CVE-2026-62752",
    "CVE-2026-62753",
    "CVE-2026-62754",
    "CVE-2026-62755",
    "CVE-2026-62757",
    "CVE-2026-62758",
    "CVE-2026-62766",
    "CVE-2026-62768",
    "CVE-2026-62769",
    "CVE-2026-62770",
    "CVE-2026-62771",
    "CVE-2026-62772",
    "CVE-2026-62773",
    "CVE-2026-62774",
    "CVE-2026-62775",
    "CVE-2026-62777",
    "CVE-2026-62779",
    "CVE-2026-62780",
    "CVE-2026-62781",
    "CVE-2026-62782",
    "CVE-2026-62783",
    "CVE-2026-62784",
    "CVE-2026-62785",
    "CVE-2026-62786",
    "CVE-2026-62788",
    "CVE-2026-62790",
    "CVE-2026-62792",
    "CVE-2026-62793",
    "CVE-2026-62795",
    "CVE-2026-62796",
    "CVE-2026-62797",
    "CVE-2026-62798",
    "CVE-2026-62799",
    "CVE-2026-62800",
    "CVE-2026-62811",
    "CVE-2026-62815",
    "CVE-2026-62816",
    "CVE-2026-62817",
    "CVE-2026-62819",
    "CVE-2026-62822",
    "CVE-2026-62832",
    "CVE-2026-62876",
    "CVE-2026-62877",
    "CVE-2026-62880",
    "CVE-2026-62881",
    "CVE-2026-62883",
    "CVE-2026-62885",
    "CVE-2026-62887",
    "CVE-2026-62888",
    "CVE-2026-62889",
    "CVE-2026-62890",
    "CVE-2026-62892",
    "CVE-2026-62894",
    "CVE-2026-62908",
    "CVE-2026-65662",
    "CVE-2026-65671",
    "CVE-2026-65672",
    "CVE-2026-65678",
    "CVE-2026-65773",
    "CVE-2026-65774",
    "CVE-2026-65775",
    "CVE-2026-65776",
    "CVE-2026-65777",
    "CVE-2026-65779",
    "CVE-2026-65780",
    "CVE-2026-65784",
    "CVE-2026-65785",
    "CVE-2026-65786",
    "CVE-2026-65787",
    "CVE-2026-65788",
    "CVE-2026-65790",
    "CVE-2026-65794",
    "CVE-2026-65795",
    "CVE-2026-65797",
    "CVE-2026-65798",
    "CVE-2026-65799",
    "CVE-2026-65814",
    "CVE-2026-66799",
    "CVE-2026-66802",
    "CVE-2026-66804",
    "CVE-2026-6726",
    "CVE-2026-6727",
    "CVE-2026-68820",
    "CVE-2026-70304",
    "CVE-2026-70307",
    "CVE-2026-70330",
    "CVE-2026-70344",
    "CVE-2026-70345",
    "CVE-2026-70346",
    "CVE-2026-70347",
    "CVE-2026-70348",
    "CVE-2026-72971"
  );
  script_xref(name:"MSKB", value:"5121000");
  script_xref(name:"MSFT", value:"MS26-5121000");

  script_name(english:"KB5121000: Windows 11 Version 26H1 Security Update (August 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 5121000. It is, therefore, affected by multiple vulnerabilities

  - Use after free in Microsoft QUIC allows an unauthorized attacker to execute code over a network.
    (CVE-2026-62815)

  - Improper neutralization of special elements used in a command ('command injection') in Windows Active
    Directory allows an unauthorized attacker to execute code over a network. (CVE-2026-49179)

  - Heap-based buffer overflow in Microsoft Local Security Authority Server (lsasrv) allows an authorized
    attacker to execute code over a network. (CVE-2026-62784)

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/5121000");
  script_set_attribute(attribute:"solution", value:
"Apply Security Update 5121000");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-62815");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/08/11");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/08/11");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/08/11");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:microsoft:windows_11_26h1");
  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 = 'MS26-08';
var kbs = make_list(
  '5121000'
);

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:28000,
                   rollup_date:'08_2026',
                   bulletin:bulletin,
                   rollup_kb_list:[5121000])
)
{
  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());
}