Security Updates for Microsoft Malware Protection Engine (July 2026)

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

include('compat.inc');

if (description)
{
  script_id(330603);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/07/30");

  script_cve_id("CVE-2026-55011", "CVE-2026-55012");
  script_xref(name:"IAVA", value:"2025-A-0719");

  script_name(english:"Security Updates for Microsoft Malware Protection Engine (July 2026)");

  script_set_attribute(attribute:"synopsis", value:
"The Microsoft Malware Protection Engine installation on the remote host is affected by multiple vulnerabilities.");
  script_set_attribute(attribute:"description", value:
"The Microsoft Malware Protection Engine installation on the remote host is missing security updates. It is,
therefore, affected by multiple vulnerabilities:

  - Integer underflow (wrap or wraparound) in Microsoft Defender allows an unauthorized attacker to execute code locally.
    (CVE-2026-55011)

  - Integer overflow or wraparound in Microsoft Defender allows an unauthorized attacker to execute code locally.
    (CVE-2026-55012)

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://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55011");
  script_set_attribute(attribute:"see_also", value:"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55012");
  script_set_attribute(attribute:"solution", value:
"Enable automatic updates to update the malware engine for the relevant antimalware applications. Refer to Knowledge Base
Article 2510781 for information on how to verify that MMPE has been updated.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/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:L/AC:L/PR:N/UI:R/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-2026-55011");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2026-55012");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_cwe_id(122, 190, 191);

  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:"2026/07/29");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:microsoft:windows");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:microsoft:windows_defender");
  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("microsoft_windows_defender_win_installed.nbin");
  script_require_keys("installed_sw/Windows Defender");

  exit(0);
}
include('vcf.inc');
include('vcf_extras.inc');

var app = 'Windows Defender';

var app_info = vcf::get_app_info(app:app, win_local:TRUE);

if (!isnull(app_info['Disabled']))
  exit(0, 'Windows Defender is disabled.');

if (isnull(app_info['Engine Version']))
  exit(0, 'Unable to get the Malware Engine Version.');

var constraints = [
  { 'max_version': '1.1.26050.11', 'fixed_version': '1.1.26060.3008'}
];

vcf::av_checks::check_version_and_report(app_info:app_info, constraints:constraints, severity:SECURITY_HOLE, check:'Engine Version');