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

high Tenable OT Security Plugin ID 505948

Synopsis

The remote OT asset is affected by a vulnerability.

Description

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.

Solution

Upgrade to firmware version 8.4.18 or later.

Plugin Details

Severity: High

ID: 505948

File Name: tenable_ot_loytecelectronics_CVE-2026-55728.nasl

Version: 1.2

Type: Remote

Family: Tenable.ot

Published: 9/7/2026

Updated: 9/8/2026

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.15

CVSS v3

Risk Factor: Medium

Base Score: 6

Temporal Score: 5.2

Vector: CVSS:3.0/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:L

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

CVSS v4

Risk Factor: High

Base Score: 7.1

Threat Score: 3.8

Threat Vector: CVSS:4.0/E:U

Vector: 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

Vulnerability Information

CPE: cpe:/o:loytec:lip-me201c_firmware, cpe:/o:loytec:lip-me202c_firmware, cpe:/o:loytec:lip-me204c_firmware

Required KB Items: Tenable.ot/LOYTECElectronics

Exploit Ease: No known exploits are available

Patch Publication Date: 6/22/2026

Vulnerability Publication Date: 6/22/2026

Reference Information

CVE: CVE-2026-55728

CWE: 121

Detections

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