Siemens RUGGEDCOM RST2428P Infinite Loop (CVE-2026-23220)

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

include('compat.inc');

if (description)
{
  script_id(505414);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/07/17");

  script_cve_id("CVE-2026-23220");
  script_xref(name:"ICSA", value:"26-188-05");

  script_name(english:"Siemens RUGGEDCOM RST2428P Infinite Loop (CVE-2026-23220)");

  script_set_attribute(attribute:"synopsis", value:
"The remote OT asset is affected by a vulnerability.");
  script_set_attribute(attribute:"description", value:
"In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix infinite loop caused by next_smb2_rcv_hdr_off reset in
error paths    The problem occurs when a signed request fails smb2
signature verification  check. In __process_request(), if
check_sign_req() returns an error,  set_smb2_rsp_status(work,
STATUS_ACCESS_DENIED) is called.  set_smb2_rsp_status() set
work->next_smb2_rcv_hdr_off as zero. By resetting
next_smb2_rcv_hdr_off to zero, the pointer to the next command in the
chain  is lost. Consequently, is_chained_smb2_message() continues to
point to  the same request header instead of advancing. If the
header's NextCommand  field is non-zero, the function returns true,
causing __handle_ksmbd_work()  to repeatedly process the same failed
request in an infinite loop.  This results in the kernel log being
flooded with bad smb2 signature  messages and high CPU usage.
This patch fixes the issue by changing the return value from
SERVER_HANDLER_CONTINUE to SERVER_HANDLER_ABORT. This ensures that
the processing loop terminates immediately rather than attempting to
continue from an invalidated offset.

This plugin only works with Tenable.ot.
Please visit https://www.tenable.com/products/tenable-ot for more information.");
  script_set_attribute(attribute:"see_also", value:"https://cert-portal.siemens.com/productcert/html/ssa-253495.html");
  script_set_attribute(attribute:"see_also", value:"https://support.industry.siemens.com/cs/ww/en/view/110002573/");
  script_set_attribute(attribute:"see_also", value:"https://www.cisa.gov/news-events/ics-advisories/ICSA-26-188-05");
  script_set_attribute(attribute:"solution", value:
"Refer to the vendor advisory.");
  script_set_cvss_base_vector("CVSS2#AV:L/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:L/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-2026-23220");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_cwe_id(835);

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/02/18");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/06/02");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/06/18");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:siemens:ruggedcom_rst2428p_firmware");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Tenable.ot");

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

  script_dependencies("tenable_ot_api_integration.nasl");
  script_require_keys("Tenable.ot/Siemens");

  exit(0);
}


include('tenable_ot_cve_funcs.inc');

get_kb_item_or_exit('Tenable.ot/Siemens');

var asset = tenable_ot::assets::get(vendor:'Siemens');

var vuln_cpes = {
    "cpe:/o:siemens:ruggedcom_rst2428p_firmware" :
        {"family" : "RuggedCom", "orderNumbers" : ['6GK6242-6PA00'], "versionEndExcluding" : "4.0"}
};

tenable_ot::cve::compare_and_report(asset:asset, cpes:vuln_cpes, severity:SECURITY_WARNING);