Elasticsearch 9.0.x < 9.4.8 / 9.5.x < 9.5.5 Incorrect Authorization (ESA-2026-199)

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

include('compat.inc');

if (description)
{
  script_id(363430);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/06");

  script_cve_id("CVE-2026-103009");

  script_name(english:"Elasticsearch 9.0.x < 9.4.8 / 9.5.x < 9.5.5 Incorrect Authorization (ESA-2026-199)");

  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 9.4.8, or 9.5.x prior to 9.5.5. It is,
therefore, affected by a vulnerability as referenced in the ESA-2026-199 advisory.

  - Authorization Bypass Through User-Controlled Key (CWE-639) in Elasticsearch can lead to Information
    Disclosure via a specially crafted cross-cluster search request that references an unauthorized shard
    identifier. Elasticsearch contains an authorization bypass weakness in its handling of cross-cluster
    search requests made through the Remote Cluster Security (RCS) 2.0 model. An authorization check validates
    a request against one identifying attribute of the target shard, while a separate, independently-supplied
    identifying attribute in the same request determines which shard is actually accessed. A holder of a
    cross-cluster API key authorized for one index can craft a request whose two identifying attributes refer
    to different indices, causing the request to be authorized against an index they can access while actually
    operating against a different, unauthorized index. This can expose that index's document contents, field
    mappings, and other metadata, and in limited cases allows modification of retention-lease state on the
    unauthorized index. (CVE-2026-103009)

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/390874");
  script_set_attribute(attribute:"solution", value:
"Upgrade to Elasticsearch version 9.4.8, or 9.5.5 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:C/I:P/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:L/PR:L/UI:N/S:U/C:H/I:L/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-2026-103009");

  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": "9.4.8"
        },
        {
          "min_version": "9.5.0",
          "fixed_version": "9.5.5"
        }
      ]
    }
  ]
};

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