Elasticsearch 9.0.x < 9.4.6 / 9.5.x < 9.5.2 DoS (ESA-2026-196)

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

include('compat.inc');

if (description)
{
  script_id(363432);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/06");

  script_cve_id("CVE-2026-103006");

  script_name(english:"Elasticsearch 9.0.x < 9.4.6 / 9.5.x < 9.5.2 DoS (ESA-2026-196)");

  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 9.0.x prior to 9.4.6, or 9.5.x prior to 9.5.2. It is,
therefore, affected by a vulnerability as referenced in the ESA-2026-196 advisory.

  - Uncontrolled Recursion (CWE-674) in Elasticsearch can lead to Denial of Service via a specially crafted,
    deeply nested request submitted to the aggregation feature of the search API. Elasticsearch contains an
    uncontrolled recursion weakness in its search aggregation processing. An authenticated user with read
    access to a single index can submit a specially crafted request containing deeply nested aggregation
    definitions. Processing this request triggers unbounded recursive execution that exhausts the server
    process's available resources, causing the affected node to terminate. The node does not recover
    automatically and requires manual intervention to restore service. (CVE-2026-103006)

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://discuss.elastic.co/t/390870");
  script_set_attribute(attribute:"solution", value:
"Upgrade to Elasticsearch version 9.4.6, or 9.5.2 or later as appropriate for your release branch.");
  script_set_attribute(attribute:"agent", value:"unix");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:N/I:N/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:L/UI:N/S:U/C:N/I:N/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-2026-103006");

  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:"2026/10/06");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/10/06");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/06");

  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:"generated_plugin", value:"current");
  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": "9.0.0",
          "fixed_version": "9.4.6"
        },
        {
          "min_version": "9.5.0",
          "fixed_version": "9.5.2"
        }
      ]
    }
  ]
};

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