Curl 7.81.0 < 8.23.0 SFTP/SCP Host Verification Bypass

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

include('compat.inc');

if (description)
{
  script_id(371153);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/23");

  script_cve_id("CVE-2026-86410");
  script_xref(name:"IAVA", value:"2026-A-1143");

  script_name(english:"Curl 7.81.0 < 8.23.0 SFTP/SCP Host Verification Bypass");

  script_set_attribute(attribute:"synopsis", value:
"The remote host has a program that is affected by a security bypass vulnerability.");
  script_set_attribute(attribute:"description", value:
"The version of curl installed on the remote host is 7.81.0 prior to 8.23.0. It is, therefore, affected by
a security bypass vulnerability:

  - A flaw in the curl command line tool's logic makes it only set SSH host verification options
    when interacting directly using SFTP or SCP, and not as a result of following a redirect.
    (CVE-2026-86410)

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://curl.se/docs/CVE-2026-86410.html");
  script_set_attribute(attribute:"solution", value:
"Upgrade Curl to version 8.23.0 or later.");
  script_set_attribute(attribute:"agent", value:"all");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N");
  script_set_attribute(attribute:"cvss_score_source", value:"manual");
  script_set_attribute(attribute:"cvss_score_rationale", value:"score from an analysis done by Tenable");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/10/14");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/10/14");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/23");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"asset_categories", value:"component");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:haxx:curl");
  script_set_attribute(attribute:"thorough_tests", value:"true");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Misc.");

  script_copyright(english:"This script is Copyright (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("curl_win_installed.nbin", "curl_nix_installed.nbin");
  script_require_keys("installed_sw/Curl");

  exit(0);
}

include('vdf.inc');

# @tvdl-content
var vuln_data = {
  'metadata': {'spec_version': '1.0'},
  'checks': [
    {
      'product': {'name': 'Curl', 'type': 'app'},
      'check_algorithm': 'default',
      'constraints': [
        {'min_version': '7.81.0', 'fixed_version': '8.23.0'}
      ]
    }
  ]
};

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