CVE-2026-55728 in LIP-ME20xC
Summary
by MITRE • 07/24/2026
Stack-based Buffer Overflow (CWE-121) in `/usr/bin/ltsudo` `cmd_ipaddr_conflict` in Loytec LIP-ME201C, L-INX, L-GATE, L-ROC, L-IOB, L-DALI, L-VIS and L-PAD through 8.4.16 on LINX-A64 allows a `superadmin`-group attacker to trigger a SUID-root process abort or potentially elevate privileges via an overly long interface-name argument.
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Analysis
by VulDB Data Team • 07/24/2026
The vulnerability described represents a critical stack-based buffer overflow affecting multiple Loytec network security devices including the LIP-ME201C, L-INX, L-GATE, L-ROC, L-IOB, L-DALI, L-VIS and L-PAD series running firmware versions through 8.4.16 on LINX-A64 architecture. This flaw exists within the `/usr/bin/ltsudo` binary specifically in the `cmd_ipaddr_conflict` function, which processes interface-name arguments during network configuration operations. The vulnerability is particularly dangerous because it operates within a SUID-root binary, meaning any successful exploitation could potentially grant attackers root-level privileges on the affected systems.
The technical implementation of this buffer overflow stems from inadequate input validation within the command-line argument processing mechanism. When an attacker provides an excessively long interface-name argument to the ltsudo utility, the program fails to properly bounds-check the input before copying it into a fixed-size stack buffer. This classic stack-based buffer overflow scenario allows memory corruption in adjacent stack locations and can be exploited to overwrite return addresses, function pointers, or other critical control data structures within the program's execution context.
From an operational perspective, this vulnerability requires an attacker to already possess credentials belonging to the superadmin group, which limits the initial attack surface but does not eliminate the severity of the potential impact. The fact that the vulnerable function operates within a SUID-root binary means that privilege escalation is theoretically possible even if the attacker cannot directly execute arbitrary code on the system. This makes the vulnerability particularly concerning for network security administrators who may have granted superadmin privileges to multiple users or systems as part of normal operational procedures.
The potential exploitation pathways for this vulnerability align with several ATT&CK tactics including privilege escalation and defense evasion, where an attacker could leverage the buffer overflow to gain root access and subsequently compromise the entire network infrastructure. The impact extends beyond simple system crashes since successful exploitation could enable persistent backdoor access, data exfiltration, or complete network compromise. Organizations using these devices should consider the vulnerability as a high-priority risk requiring immediate attention, particularly in environments where network security is critical and where superadmin credentials might be accessible to unauthorized personnel.
Security practitioners should implement immediate mitigations including firmware updates from Loytec, input validation restrictions on interface-name arguments, and monitoring for suspicious command-line inputs. The vulnerability demonstrates the importance of secure coding practices around buffer management and the dangers of SUID binaries that handle user-supplied data without proper bounds checking. This case study underscores why organizations must maintain rigorous security testing protocols, particularly for critical system utilities that operate with elevated privileges and handle untrusted input from network interfaces or command-line parameters. The vulnerability also highlights the need for comprehensive access control measures to prevent unauthorized users from gaining superadmin privileges in the first place.
Reference to CWE-121 provides standardized context for this specific class of buffer overflow vulnerability, while the ATT&CK framework helps identify the operational implications and potential attack vectors that could be exploited by threat actors. The combination of SUID execution context with stack-based buffer overflow creates a particularly dangerous scenario that requires immediate remediation through both software patches and operational security improvements to prevent unauthorized privilege escalation attacks.