Apache Struts 2.5.14 <= 2.5.33 / 6.x < 6.12.0 / 7.x < 7.4.0 Denial of Service (S2-076)

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

include('compat.inc');

if (description)
{
  script_id(364467);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/12");

  script_cve_id("CVE-2026-104712");
  script_xref(name:"IAVA", value:"2026-A-1088");

  script_name(english:"Apache Struts 2.5.14 <= 2.5.33 / 6.x < 6.12.0 / 7.x < 7.4.0 Denial of Service (S2-076)");

  script_set_attribute(attribute:"synopsis", value:
"The Apache Struts install on the remote host is affected by a denial of service vulnerability.");
  script_set_attribute(attribute:"description", value:
"The version of Apache Struts installed on the remote host is 2.5.14 through 2.5.33, or 6.x prior to 6.12.0, or 7.x
prior to 7.4.0. It is, therefore, affected by a denial of service vulnerability, as referenced in the S2-076 advisory:

  - Asymmetric resource consumption (amplification) vulnerability in Apache Struts. When a request parameter is
    bound to an arbitrary-precision decimal (java.math.BigDecimal) property that is then rendered through the
    Struts tag library, the framework can produce a response many orders of magnitude larger than the request,
    allowing an unauthenticated remote attacker to exhaust server CPU and outbound network capacity with sustained
    low-volume traffic. Applications that do not bind request parameters to BigDecimal properties, or never render
    such a property through the Struts tag library, are not affected. (CVE-2026-104712)

Nessus cannot verify whether the application binds request parameters to BigDecimal properties and renders them
through the Struts tag library, so this finding is flagged as a potential vulnerability.

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://cwiki.apache.org/confluence/spaces/WW/pages/446071762/S2-076");
  script_set_attribute(attribute:"see_also", value:"https://struts.apache.org/announce-2026");
  script_set_attribute(attribute:"solution", value:
"Upgrade to Apache Struts version 6.12.0 / 7.4.0 or later. Alternatively, apply the workaround as referenced in the
vendor's security bulletin.");
  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: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-2026-104712");

  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:"2026/10/05");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/10/02");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/09");

  script_set_attribute(attribute:"potential_vulnerability", value:"true");
  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:apache:struts");
  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:"Misc.");

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

  script_dependencies("struts_detect_win.nbin", "struts_detect_nix.nbin");
  script_require_keys("Settings/ParanoidReport");
  script_require_ports("installed_sw/Apache Struts");

  exit(0);
}

include('vdf.inc');

if (report_paranoia < 2)
  audit(AUDIT_PARANOID);

# @tvdl-content
var vuln_data = {
  'metadata': {'spec_version': '1.0'},
  'checks': [
    {
      'product': {'name': 'Apache Struts', 'type': 'app'},
      'check_algorithm': 'default',
      'potential_vulnerability': {
        'missing_config_check': true
      },
      'requires': [
        {'scope': 'target', 'match': {'paranoia': true}}
      ],
      'constraints': [
        {'min_version': '2.5.14', 'max_version': '2.5.33', 'fixed_display': '6.12.0 / 7.4.0'},
        {'min_version': '6.0.0', 'fixed_version': '6.12.0'},
        {'min_version': '7.0.0', 'fixed_version': '7.4.0'}
      ]
    }
  ]
};

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