CVE-2026-75164 in Firmware
Summary
by MITRE • 09/04/2026
An arbitrary file read vulnerability in /cgi-bin/ugwdownload.cgi of MBS-Solutions X-Serie Gateway firmware V6_00_05 allows a remote authenticated user with the low-privileged Standard role to retrieve arbitrary files from the device filesystem via the file query string parameter.
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Analysis
by VulDB Data Team • 09/04/2026
The vulnerability identified in the MBS-Solutions X-Series Gateway firmware version 6_00_05 represents a critical security flaw within the web-based management interface, specifically located in the /cgi-bin/ugwdownload.cgi script. This component is designed to facilitate file downloads for users who require access to specific configuration or log files from the gateway device. However, the implementation fails to adequately sanitize user-supplied input before processing it against the local filesystem. The core technical flaw lies in the lack of proper path canonicalization and boundary checking when handling the file query string parameter. An attacker can manipulate this parameter by injecting directory traversal sequences, such as ../ or ..\ depending on the underlying operating system environment, to navigate outside the intended download directory structure. This allows the script to resolve paths that point to sensitive areas of the device's filesystem which are not meant for public access via the web interface.
From an operational perspective, this vulnerability enables a remote authenticated attacker with low-privileged Standard role credentials to perform arbitrary file reads on the target system. The requirement for authentication does not mitigate the risk because standard user accounts often possess sufficient privileges to interact with the download functionality but lack the administrative controls needed to restrict their own actions within that specific module. By exploiting this flaw, an adversary can extract sensitive configuration files containing network topology details, default credentials embedded in setup scripts, private keys used for SSL/TLS communications, or internal log files that may reveal system architecture and running processes. The ability to read these files provides the attacker with significant reconnaissance capabilities, potentially leading to further exploitation such as credential stuffing attacks against other services or deeper penetration into the network segment protected by this gateway.
This vulnerability aligns directly with Common Weakness Enumeration (CWE) ID 22, which defines Improper Limitation of a Pathname to a Restricted Directory, commonly known as path traversal. The attack vector is classified under MITRE ATT&CK technique T1083, File and Directory Discovery, specifically through the mechanism of accessing files in non-standard directories or locations that are not typically accessible by standard users. While the initial access requires authentication, which places it outside the scope of remote unauthenticated exploitation techniques like T1596 (Gather Victim Host Information), the low privilege requirement makes this a high-risk issue for environments where user accounts may be compromised through phishing or weak password policies. The impact is primarily confidentiality-related, as the attacker gains read-only access to system resources without necessarily achieving code execution on the device itself.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. The most effective solution is to apply the firmware update provided by MBS-Solutions that addresses this specific flaw in version 6_00_05 or later releases, ensuring that the input validation logic correctly restricts file access to a predefined whitelist of allowed files or enforces strict path canonicalization before any filesystem operations are performed. If an immediate patch is unavailable, network-level controls should be implemented to restrict access to the /cgi-bin/ugwdownload.cgi endpoint only from trusted management subnets using firewall rules or VLAN segmentation. Additionally, implementing Web Application Firewall (WAF) signatures capable of detecting directory traversal patterns in query parameters can provide a layer of defense against exploitation attempts. It is also recommended to review user privilege assignments within the gateway interface, ensuring that standard users do not have access to download functionalities unless absolutely necessary for their operational role, thereby reducing the attack surface available to compromised low-privilege accounts.