Microsoft .NET Framework (September 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(344819);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/11");

  script_cve_id("CVE-2026-62886", "CVE-2026-69522");
  script_xref(name:"MSKB", value:"5126043");
  script_xref(name:"MSKB", value:"5126044");
  script_xref(name:"MSKB", value:"5126045");
  script_xref(name:"MSKB", value:"5126046");
  script_xref(name:"MSKB", value:"5126047");
  script_xref(name:"MSKB", value:"5126048");
  script_xref(name:"MSKB", value:"5126049");
  script_xref(name:"MSKB", value:"5126050");
  script_xref(name:"MSKB", value:"5126051");
  script_xref(name:"MSKB", value:"5126052");
  script_xref(name:"MSKB", value:"5126053");
  script_xref(name:"MSKB", value:"5126421");
  script_xref(name:"MSKB", value:"5126422");
  script_xref(name:"MSKB", value:"5126424");
  script_xref(name:"MSFT", value:"MS26-5126043");
  script_xref(name:"MSFT", value:"MS26-5126044");
  script_xref(name:"MSFT", value:"MS26-5126045");
  script_xref(name:"MSFT", value:"MS26-5126046");
  script_xref(name:"MSFT", value:"MS26-5126047");
  script_xref(name:"MSFT", value:"MS26-5126048");
  script_xref(name:"MSFT", value:"MS26-5126049");
  script_xref(name:"MSFT", value:"MS26-5126050");
  script_xref(name:"MSFT", value:"MS26-5126051");
  script_xref(name:"MSFT", value:"MS26-5126052");
  script_xref(name:"MSFT", value:"MS26-5126053");
  script_xref(name:"MSFT", value:"MS26-5126421");
  script_xref(name:"MSFT", value:"MS26-5126422");
  script_xref(name:"MSFT", value:"MS26-5126424");
  script_xref(name:"IAVA", value:"2026-A-0965");

  script_name(english:"Microsoft .NET Framework (September 2026)");

  script_set_attribute(attribute:"synopsis", value:
"The Microsoft .NET Framework installation on the remote host is affected by multiple vulnerabilities.");
  script_set_attribute(attribute:"description", value:
"The Microsoft .NET Framework installation on the remote host is missing a security update. It is, therefore, affected by
the following vulnerabilities:

  - Integer overflow or wraparound in .NET allows an unauthorized attacker to elevate privileges locally.
    (CVE-2026-62886)

  - Heap-based buffer overflow in Visual Studio allows an unauthorized attacker to execute code over a network.
    (CVE-2026-69522)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"solution", value:
"Microsoft has released the following security updates to address this issue:
  -KB5126043
  -KB5126044
  -KB5126045
  -KB5126046
  -KB5126047
  -KB5126048
  -KB5126049
  -KB5126050
  -KB5126051
  -KB5126052
  -KB5126053
  -KB5126421
  -KB5126422
  -KB5126424");
  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:R/S:U/C:H/I:H/A:H");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-69522");

  script_cwe_id(122, 190);

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/09/08");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/09/08");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/11");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:microsoft:.net_framework");
  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_dotnet_rollup.nasl", "smb_hotfixes.nasl", "ms_bulletin_checks_possible.nasl", "microsoft_net_framework_installed.nasl");
  script_require_keys("SMB/MS_Bulletin_Checks/Possible");
  script_require_ports(139, 445, "Host/patch_management_checks");

  exit(0);
}

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

get_kb_item_or_exit('SMB/MS_Bulletin_Checks/Possible');

var bulletin = 'MS26-09';
var kbs = make_list(
  '5126043',
  '5126044',
  '5126045',
  '5126046',
  '5126047',
  '5126048',
  '5126049',
  '5126050',
  '5126051',
  '5126052',
  '5126053',
  '5126421',
  '5126422',
  '5126424'
);

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

var app = 'Microsoft .NET Framework';
get_install_count(app_name:app, exit_if_zero:TRUE);
var installs = get_combined_installs(app_name:app);

var install, version;
var vuln = 0;

if (installs[0] == 0)
{
  foreach install (installs[1])
  {
    version = install['version'];
    if( version != UNKNOWN_VER &&
        smb_check_dotnet_rollup(rollup_date:'09_2026', dotnet_ver:version))
      vuln++;
  }
}
if(vuln)
{
  hotfix_security_hole();
  hotfix_check_fversion_end();
  exit(0);
}
else
{
  hotfix_check_fversion_end();
  audit(AUDIT_HOST_NOT, 'affected');
}