Security Update for Microsoft .NET Core (May 2026)

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

include('compat.inc');

if (description)
{
  script_id(314679);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/05/15");

  script_cve_id(
    "CVE-2026-32175",
    "CVE-2026-32177",
    "CVE-2026-35433",
    "CVE-2026-42899"
  );
  script_xref(name:"MSKB", value:"5093446");
  script_xref(name:"MSKB", value:"5093447");
  script_xref(name:"MSKB", value:"5093448");
  script_xref(name:"MSFT", value:"MS26-5093446");
  script_xref(name:"MSFT", value:"MS26-5093447");
  script_xref(name:"MSFT", value:"MS26-5093448");
  script_xref(name:"IAVA", value:"2026-A-0463");
  script_xref(name:"IAVA", value:"2026-A-0474");
  script_xref(name:"IAVA", value:"2026-A-0460");

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

  script_set_attribute(attribute:"synopsis", value:
"The remote Windows host is affected by a .NET Core vulnerability");
  script_set_attribute(attribute:"description", value:
"The version of tested product installed on the remote host is prior to tested version. It is, therefore, affected by
multiple vulnerabilities as referenced in the vendor advisory.

  - A tampering vulnerability exists when .NET Core improperly handles specially crafted files. An attacker
    who successfully exploited this vulnerability could write arbitrary files and directories to certain
    locations on a vulnerable system. However, an attacker would have limited control over the destination of
    the files and directories. To exploit the vulnerability, an attacker must send a specially crafted file to
    a vulnerable system. The security update fixes the vulnerability by ensuring .NET Core properly handles
    files. (CVE-2026-32175)

  - Heap-based buffer overflow in .NET allows an unauthorized attacker to elevate privileges locally.
    (CVE-2026-32177)

  - Improper input validation in .NET allows an unauthorized attacker to elevate privileges locally.
    (CVE-2026-35433)

  - Loop with unreachable exit condition ('infinite loop') in ASP.NET Core allows an unauthorized attacker to
    deny service over a network. (CVE-2026-42899)

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://dotnet.microsoft.com/download/dotnet/8.0");
  script_set_attribute(attribute:"see_also", value:"https://dotnet.microsoft.com/download/dotnet/9.0");
  script_set_attribute(attribute:"see_also", value:"https://dotnet.microsoft.com/download/dotnet/10.0");
  # https://github.com/dotnet/core/blob/main/release-notes/8.0/8.0.27/8.0.27.md
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?b4fa7f33");
  # https://github.com/dotnet/core/blob/master/release-notes/9.0/9.0.16/9.0.16.md
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?74ce176b");
  # https://github.com/dotnet/core/blob/main/release-notes/10.0/10.0.8/10.0.8.md
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?b7118ca9");
  script_set_attribute(attribute:"see_also", value:"https://github.com/dotnet/announcements/issues/396");
  script_set_attribute(attribute:"see_also", value:"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-32175");
  script_set_attribute(attribute:"see_also", value:"https://github.com/dotnet/announcements/issues/399");
  script_set_attribute(attribute:"see_also", value:"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-32177");
  script_set_attribute(attribute:"see_also", value:"https://github.com/dotnet/announcements/issues/398");
  script_set_attribute(attribute:"see_also", value:"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-35433");
  script_set_attribute(attribute:"see_also", value:"https://github.com/dotnet/announcements/issues/397");
  script_set_attribute(attribute:"see_also", value:"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42899");
  script_set_attribute(attribute:"see_also", value:"https://support.microsoft.com/help/5093446");
  script_set_attribute(attribute:"see_also", value:"https://support.microsoft.com/help/5093447");
  script_set_attribute(attribute:"see_also", value:"https://support.microsoft.com/help/5093448");
  script_set_attribute(attribute:"solution", value:
"Update .NET Core, remove vulnerable packages and refer to vendor advisory.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-35433");

  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:"2026/05/12");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/05/12");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/05/14");

  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': '8.0.27'
    },{
      'min_version': '9',
      'fixed_version': '9.0.16'
    },{
      'min_version': '10',
      'fixed_version': '10.0.8'
    }]
  }]
};

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