Elasticsearch 8.18.x < 8.19.20 / 9.0.x < 9.4.5 / 9.5.x < 9.5.1 Information Disclosure (ESA-2026-141)

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

include('compat.inc');

if (description)
{
  script_id(344304);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/10");

  script_cve_id("CVE-2026-78605");

  script_name(english:"Elasticsearch 8.18.x < 8.19.20 / 9.0.x < 9.4.5 / 9.5.x < 9.5.1 Information Disclosure (ESA-2026-141)");

  script_set_attribute(attribute:"synopsis", value:
"The remote host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The version of Elasticsearch installed on the remote host is 8.18.x prior to 8.19.20, or 9.0.x prior to 9.4.5, or 9.5.x
prior to 9.5.1. It is, therefore, affected by a vulnerability as referenced in the ESA-2026-141 advisory.

  - Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling') (CWE-444) in Elasticsearch can lead
    to information disclosure via HTTP Request Smuggling (CAPEC-33). Under specific proxy deployment
    configurations, a network attacker could obtain confidential responses intended for other authenticated
    users. (CVE-2026-78605)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version
number.");
  # https://discuss.elastic.co/t/elasticsearch-8-19-20-9-4-5-9-5-1-security-update-esa-2026-141/390092
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?6d15741b");
  script_set_attribute(attribute:"solution", value:
"Upgrade to Elasticsearch version 8.19.20, 9.4.5, or 9.5.1 or later as appropriate for your release branch.");
  script_set_attribute(attribute:"agent", value:"unix");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:N/C:C/I:N/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-78605");

  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:"2026/09/01");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/09/01");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/09");

  script_set_attribute(attribute:"plugin_type", value:"combined");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:elasticsearch:elasticsearch");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:elastic:elasticsearch");
  script_set_attribute(attribute:"thorough_tests", value:"true");
  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("elasticsearch_detect.nbin", "elastic_elasticsearch_nix_installed.nbin");
  script_require_keys("installed_sw/Elasticsearch");

  exit(0);
}

include('vdf.inc');

# @tvdl-content
var vuln_data = {
  'metadata': {'spec_version': '1.0'},
  'checks': [
    {
      'product': {'name': 'Elasticsearch', 'type': 'app'},
      'check_algorithm': 'default',
      'constraints': [
        {'min_version': '8.18.0', 'fixed_version': '8.19.20'},
        {'min_version': '9.0.0', 'fixed_version': '9.4.5'},
        {'min_version': '9.5.0', 'fixed_version': '9.5.1'}
      ]
    }
  ]
};

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