CVE-2026-82765 in FX5000
Summary
by MITRE • 09/14/2026
Path traversal vulnerability exists in Contec FX5000 series, FX4000 series, and FX3000 series. If this vulnerability is exploited, arbitrary files on the server may be viewed and/or altered by an attacker who can access the product via FTP.
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Analysis
by VulDB Data Team • 09/14/2026
The identified security flaw represents a critical path traversal vulnerability affecting multiple models within the Contec industrial automation portfolio, specifically the FX5000, FX4000, and FX3000 series devices. This type of weakness is fundamentally rooted in improper validation of user-supplied input, where the application fails to sufficiently sanitize file paths before using them in operations that interact with the underlying operating system or filesystem. In this specific context, the vulnerability manifests through the File Transfer Protocol (FTP) interface provided by these industrial controllers and communication gateways. FTP services are commonly used for firmware updates, configuration backups, and log retrieval in industrial environments, making their security posture paramount to maintaining operational integrity.
From a technical perspective, the flaw allows an attacker who has valid credentials or can otherwise access the product via FTP to manipulate directory traversal sequences within file path parameters. By injecting special characters such as dot-dot-slash (../) into filenames or directory names during upload or download operations, an adversary can break out of the intended restricted directory structure. This mechanism bypasses standard chroot jails or sandboxing measures that are typically configured to limit user access to specific folders for security isolation. Consequently, the attacker gains the ability to read files located outside the designated FTP root directory and potentially write or overwrite arbitrary system files depending on the permissions associated with the FTP service account.
The operational impact of this vulnerability is severe due to the nature of industrial control systems which often run with elevated privileges to ensure reliable hardware interaction. If an attacker successfully exploits this path traversal flaw, they can access sensitive configuration files that contain network settings, authentication credentials, or proprietary logic parameters. Furthermore, the ability to alter arbitrary files opens the door for persistent backdoors, malicious firmware injection, or disruption of critical services by corrupting essential system binaries and libraries. This level of control effectively compromises the confidentiality, integrity, and availability of the industrial asset, potentially leading to unauthorized process manipulation or complete system failure in a production environment.
This vulnerability aligns with Common Weakness Enumeration identifier CWE-22, which defines Improper Limitation of a Pathname to a Restricted Directory. It also maps directly to MITRE ATT&CK technique T1083, File and Directory Discovery, as well as T1564, Hidden Files and Directories if the attacker uses traversal to access hidden system files. The exploitation vector is classified under Network Access with Authentication Required, indicating that while remote network connectivity is necessary, valid credentials are typically needed to trigger the flaw unless additional authentication bypasses exist.
Mitigation strategies must focus on both immediate remediation and long-term architectural hardening. Vendors should release firmware updates that enforce strict input validation for all file path operations within the FTP service implementation. This includes rejecting any path components containing traversal sequences or normalizing paths before processing to ensure they remain within the allowed directory boundaries. Administrators currently operating these devices should restrict FTP access to trusted management networks only, implement strong password policies, and consider disabling the FTP service entirely in favor of more secure alternatives like SFTP if supported by newer firmware versions. Regular vulnerability assessments and penetration testing focused on industrial protocol interfaces are essential to identify similar weaknesses before they can be exploited in live environments.