Security Updates for Microsoft Excel Products (September 2026)

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

include('compat.inc');

if (description)
{
  script_id(344285);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/11");

  script_cve_id(
    "CVE-2026-78512",
    "CVE-2026-78518",
    "CVE-2026-81386",
    "CVE-2026-81387",
    "CVE-2026-81388",
    "CVE-2026-81389",
    "CVE-2026-81390",
    "CVE-2026-81391",
    "CVE-2026-81392",
    "CVE-2026-81393",
    "CVE-2026-81394",
    "CVE-2026-81395",
    "CVE-2026-81396",
    "CVE-2026-81397",
    "CVE-2026-81398",
    "CVE-2026-81399",
    "CVE-2026-81400",
    "CVE-2026-81401",
    "CVE-2026-81947",
    "CVE-2026-81948",
    "CVE-2026-81949",
    "CVE-2026-81950",
    "CVE-2026-81951",
    "CVE-2026-81953",
    "CVE-2026-81954",
    "CVE-2026-81956",
    "CVE-2026-81957",
    "CVE-2026-81958",
    "CVE-2026-81959",
    "CVE-2026-81960",
    "CVE-2026-85875"
  );
  script_xref(name:"MSKB", value:"5002914");
  script_xref(name:"MSFT", value:"MS26-5002914");
  script_xref(name:"IAVA", value:"2026-A-0959");

  script_name(english:"Security Updates for Microsoft Excel Products (September 2026)");

  script_set_attribute(attribute:"synopsis", value:
"The Microsoft Excel Products are affected by multiple vulnerabilities.");
  script_set_attribute(attribute:"description", value:
"The Microsoft Excel Products are missing a security update. They are, therefore, affected by multiple vulnerabilities:

  - Numeric truncation error in Microsoft Office Word allows an unauthorized attacker to execute code
    over a network. (CVE-2026-78512)

  - Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to execute code over a
    network. (CVE-2026-78518)

  - Heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code
    locally. (CVE-2026-81386, CVE-2026-81389, CVE-2026-81397, CVE-2026-81398, CVE-2026-81947,
    CVE-2026-81948, CVE-2026-81951, CVE-2026-81959, CVE-2026-81960)

  - Exposure of sensitive system information to an unauthorized control sphere in Microsoft Office Excel
    allows an unauthorized attacker to disclose information locally. (CVE-2026-81387, CVE-2026-81394)

  - Stack-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute
    code locally. (CVE-2026-81388, CVE-2026-81396, CVE-2026-81953)

  - Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information
    locally. (CVE-2026-81390, CVE-2026-81392, CVE-2026-81393, CVE-2026-81395, CVE-2026-81400,
    CVE-2026-85875)

  - Use of uninitialized resource in Microsoft Office Excel allows an unauthorized attacker to disclose
    information locally. (CVE-2026-81391, CVE-2026-81958)

  - Buffer over-read in Microsoft Office Excel allows an unauthorized attacker to disclose information
    locally. (CVE-2026-81399)

  - Access of resource using incompatible type ('type confusion') in Microsoft Office Excel allows an
    unauthorized attacker to disclose information locally. (CVE-2026-81401)

  - Integer overflow or wraparound in Microsoft Office Excel allows an unauthorized attacker to execute
    code locally. (CVE-2026-81949)

  - Double free in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
    (CVE-2026-81950)

  - Use after free in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
    (CVE-2026-81954)

  - Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to execute code
    locally. (CVE-2026-81956, CVE-2026-81957)

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://support.microsoft.com/en-us/help/5002914");
  script_set_attribute(attribute:"solution", value:
"Microsoft has released KB5002914 to address this issue.");
  script_set_cvss_base_vector("CVSS2#AV:N/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:N/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-2026-78518");

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

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

  exit(0);
}

include('vcf_extras_office.inc');

var bulletin = 'MS26-09';
var kbs = ['5002914'];

var constraints = [
    { 'kb':'5002914', 'channel':'MSI', 'fixed_version': '16.0.5569.1003', 'sp' : 0}
];

vcf::microsoft::office_product::check_version_and_report(
  kbs:kbs,
  constraints:constraints,
  severity:SECURITY_HOLE,
  bulletin:bulletin,
  subproduct:'Excel'
);