Security Update for Microsoft .NET Core (September 2026)

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

include('compat.inc');

if (description)
{
  script_id(344808);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/11");

  script_cve_id(
    "CVE-2026-69439",
    "CVE-2026-69522",
    "CVE-2026-71328"
  );
  script_xref(name:"IAVA", value:"2026-A-0949");

  script_name(english:"Security Update for Microsoft .NET Core (September 2026)");

  script_set_attribute(attribute:"synopsis", value:
"The Microsoft .NET Core installations on the remote host are affected by multiple vulnerabilities.");
  script_set_attribute(attribute:"description", value:
"The Microsoft .NET Core installations on the remote host are missing a security update. It is, therefore, affected by
multiple vulnerabilities as referenced in the vendor advisory.

  - Heap-based buffer overflow in .NET and Visual Studio allows an unauthorized attacker to elevate privileges
    over a network. (CVE-2026-69439)

  - Heap-based buffer overflow in .NET and Visual Studio allows an unauthorized attacker to execute code over
    a network. (CVE-2026-69522, CVE-2026-71328)

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://github.com/dotnet/announcements/issues/438");
  script_set_attribute(attribute:"see_also", value:"https://github.com/dotnet/announcements/issues/439");
  script_set_attribute(attribute:"see_also", value:"https://github.com/dotnet/announcements/issues/440");
  script_set_attribute(attribute:"see_also", value:"https://support.microsoft.com/help/5126104");
  script_set_attribute(attribute:"see_also", value:"https://support.microsoft.com/help/5126105");
  script_set_attribute(attribute:"see_also", value:"https://support.microsoft.com/help/5126106");
  script_set_attribute(attribute:"see_also", value:"https://dotnet.microsoft.com/download/dotnet/8.0");
  # https://github.com/dotnet/core/blob/main/release-notes/8.0/8.0.31/8.0.31.md
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?98a9ec7b");
  script_set_attribute(attribute:"see_also", value:"https://dotnet.microsoft.com/download/dotnet/9.0");
  # https://github.com/dotnet/core/blob/main/release-notes/9.0/9.0.20/9.0.20.md
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?952001e2");
  script_set_attribute(attribute:"see_also", value:"https://dotnet.microsoft.com/download/dotnet/10.0");
  # https://github.com/dotnet/core/blob/main/release-notes/10.0/10.0.12/10.0.12.md
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?c8b12f3f");
  script_set_attribute(attribute:"solution", value:
"Update .NET Core, remove vulnerable packages and refer to vendor advisory.");
  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);

  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_core");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

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

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

  script_dependencies("microsoft_dotnet_core_win.nbin");
  script_require_keys("installed_sw/.NET Core Windows");

  exit(0);
}

include('vdf.inc');

# @tvdl-content
var vuln_data = {
  'metadata': {'spec_version': '1.0'},
  'requires': [{'scope': 'target', 'match': {'os': 'windows'}}],
  'checks': [{
    'product': {'name': '.NET Core Windows', 'type': 'app'},
    'check_algorithm': 'default',
    'constraints': [{
      'min_version': '8',
      'fixed_version': '8.0.31'
    },{
      'min_version': '9',
      'fixed_version': '9.0.20'
    },{
      'min_version': '10',
      'fixed_version': '10.0.12'
    }]
  }]
};

var result = vdf::check_and_report(vuln_data:vuln_data, severity:SECURITY_HOLE);
vdf::handle_check_and_report_errors(vdf_result:result);