Security Update for Microsoft ASP.NET Core (July 2026)

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

include('compat.inc');

if (description)
{
  script_id(326871);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/07/15");

  script_cve_id("CVE-2026-47300", "CVE-2026-47303");

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

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

  - Incorrect implementation of authentication algorithm in ASP.NET Core allows an authorized attacker to
    elevate privileges over a network. (CVE-2026-47300)

  - Authentication bypass by assumed-immutable data in ASP.NET Core allows an authorized attacker to elevate
    privileges over a network. (CVE-2026-47303)

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/409");
  script_set_attribute(attribute:"see_also", value:"https://github.com/dotnet/announcements/issues/411");
  script_set_attribute(attribute:"see_also", value:"https://dotnet.microsoft.com/en-us/download/dotnet/8.0");
  # https://github.com/dotnet/core/blob/main/release-notes/8.0/8.0.29/8.0.29.md
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?666098d4");
  script_set_attribute(attribute:"see_also", value:"https://dotnet.microsoft.com/en-us/download/dotnet/9.0");
  # https://github.com/dotnet/core/blob/master/release-notes/9.0/9.0.18/9.0.18.md
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?f2dfe152");
  script_set_attribute(attribute:"see_also", value:"https://dotnet.microsoft.com/en-us/download/dotnet/10.0");
  # https://github.com/dotnet/core/blob/main/release-notes/10.0/10.0.10/10.0.10.md
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?d1fdace6");
  script_set_attribute(attribute:"see_also", value:"https://support.microsoft.com/kb/5104032");
  script_set_attribute(attribute:"see_also", value:"https://support.microsoft.com/kb/5104033");
  script_set_attribute(attribute:"see_also", value:"https://support.microsoft.com/kb/5104034");
  script_set_attribute(attribute:"solution", value:
"Update ASP.NET Core, remove vulnerable packages and refer to vendor advisory.");
  script_set_cvss_base_vector("CVSS2#AV:N/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:N/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-2026-47300");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2026-47303");

  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:"2026/07/14");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/07/14");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/07/14");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:microsoft:.net_core");
  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_asp_dotnet_core_win.nbin");
  script_require_keys("SMB/Registry/Enumerated", "installed_sw/ASP .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': 'ASP .NET Core Windows', 'type': 'app'},
    'check_algorithm': 'default',
    'constraints': [{
      'min_version': '8',
      'fixed_version': '8.0.29'
    },{
      'min_version': '9',
      'fixed_version': '9.0.18'
    },{
      'min_version': '10',
      'fixed_version': '10.0.10'
    }]
  }]
};

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