LOYTEC L-IP BACnet/IP Routers Stack-based Buffer Overflow (CVE-2026-55728)

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

include('compat.inc');

if (description)
{
  script_id(505948);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/08");

  script_cve_id("CVE-2026-55728");

  script_name(english:"LOYTEC L-IP BACnet/IP Routers Stack-based Buffer Overflow (CVE-2026-55728)");

  script_set_attribute(attribute:"synopsis", value:
"The remote OT asset is affected by a vulnerability.");
  script_set_attribute(attribute:"description", value:
"The 'cmd_ipaddr_conflict' subcommand of the SUID-root
'/usr/bin/ltsudo' utility on a LOYTEC L-IP BACnet/IP router
copies a user-supplied network interface name into a fixed
20-byte stack buffer using 'strcpy()' without bounds checking.
A 'superadmin'-group attacker can supply an overly long
interface name to overflow the buffer, aborting the SUID-root
process and potentially gaining leverage toward privilege
escalation.

This plugin only works with Tenable.ot.
Please visit https://www.tenable.com/products/tenable-ot for more information.");
  # https://www.loytec.com/support/product-security/advisories/8523-dibt-cve-20260526-0005-stack-buffer-overflow-in-cmd_ipaddr_conflict-low
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?5eeeb0c7");
  script_set_attribute(attribute:"solution", value:
"Upgrade to firmware version 8.4.18 or later.");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:L");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss4_vector", value:"CVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:U");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-55728");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_cwe_id(121);

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/06/22");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/06/22");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/07");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:loytec:lip-me201c_firmware");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:loytec:lip-me202c_firmware");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:loytec:lip-me204c_firmware");
  script_set_attribute(attribute:"generated_plugin", value:"former");
  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/LOYTECElectronics");

  exit(0);
}


include('tenable_ot_cve_funcs.inc');

get_kb_item_or_exit('Tenable.ot/LOYTECElectronics');

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

var vuln_cpes = {
    "cpe:/o:loytec:lip-me201c_firmware" :
        {"versionEndExcluding" : "8.4.18", "family" : "LIPBacnetRouters"},
    "cpe:/o:loytec:lip-me202c_firmware" :
        {"versionEndExcluding" : "8.4.18", "family" : "LIPBacnetRouters"},
    "cpe:/o:loytec:lip-me204c_firmware" :
        {"versionEndExcluding" : "8.4.18", "family" : "LIPBacnetRouters"}
};

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