Notepad++ <= 8.9.3 Stack-based Buffer Overflow (CVE-2026-5525)

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

include('compat.inc');

if (description)
{
  script_id(306546);
  script_version("1.4");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/05/08");

  script_cve_id("CVE-2026-5525");
  script_xref(name:"IAVA", value:"2026-A-0321-S");

  script_name(english:"Notepad++ <= 8.9.3 Stack-based Buffer Overflow (CVE-2026-5525)");

  script_set_attribute(attribute:"synopsis", value:
"A text editor on the remote Windows host is affected by a stack-based buffer overflow vulnerability.");
  script_set_attribute(attribute:"description", value:
"The version of Notepad++ installed on the remote host is 8.9.3 or earlier. It is, therefore,
affected by a stack-based buffer overflow vulnerability:

  - A stack-based buffer overflow exists in the file drop handler component (WM_DROPFILES). When
    a user drags and drops a directory path of exactly 259 characters without a trailing backslash,
    the application appends a backslash and null terminator without proper bounds checking, resulting
    in a stack buffer overflow and application crash. (CVE-2026-5525)

Note that Nessus has not tested for this issue but has instead relied only on the application's
self-reported version number.");
  script_set_attribute(attribute:"see_also", value:"https://github.com/notepad-plus-plus/notepad-plus-plus/issues/17921");
  script_set_attribute(attribute:"see_also", value:"https://github.com/notepad-plus-plus/notepad-plus-plus/pull/17930");
  # https://github.com/notepad-plus-plus/notepad-plus-plus/commit/bfe7514d68bc559534c046c4ef2d1865267aa2b0
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?edb17e85");
  script_set_attribute(attribute:"solution", value:
"Upgrade to a version of Notepad++ later than 8.9.3 when available.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:H/Au:N/C:C/I:C/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss4_vector", value:"CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:U");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-5525");

  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:"2026/03/31");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/04/15");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:notepad-plus-plus:notepad\+\+");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_set_attribute(attribute:"thorough_tests", value:"true");
  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("notepad_plus_plus_win_installed.nbin");
  script_require_keys("installed_sw/Notepad++", "SMB/Registry/Enumerated");

  exit(0);
}

include('vdf.inc');

# @tvdl-content
var vuln_data = {
  'metadata': {'spec_version': '1.0'},
  'requires': [
    {'scope': 'target', 'match': {'os': 'windows'}}
  ],
  'checks': [
    {
      'product': {'name': 'Notepad++', 'type': 'app'},
      'check_algorithm': 'default',
      'constraints': [
        {'max_version': '8.9.3', 'fixed_display': 'See vendor advisory'}
      ]
    }
  ]
};

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