CVE-2026-71453 in EasyIO FS32
Summary
by MITRE • 10/02/2026
- External Control of File Name or Path vulnerability in Johnson Controls EasyIO FS32 allows - traversal attack.
This issue affects EasyIO FS32: before 3.0b63.
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Analysis
by VulDB Data Team • 10/02/2026
The identified vulnerability represents a critical security flaw within the Johnson Controls EasyIO FS32 firmware, specifically affecting versions prior to 3.0b63. This weakness is classified as an External Control of File Name or Path vulnerability, which falls under the broader category of path traversal attacks. In this context, the software fails to properly sanitize user-supplied input before using it in file operations. An attacker can exploit this lack of validation by injecting maliciously crafted directory sequences into input fields that are processed by the application's file handling mechanisms. This allows the adversary to manipulate the intended file path, effectively bypassing security restrictions and accessing files or directories outside of the restricted working environment defined by the application’s design.
The technical mechanism behind this flaw relies on the improper neutralization of special elements used in file paths, commonly known as directory traversal sequences such as dot-dot-slash (../). When the EasyIO FS32 processes requests that involve reading from or writing to the local filesystem without rigorous validation, an attacker can construct a payload that navigates up the directory tree. By doing so, they can access sensitive system files, configuration data, logs containing potentially confidential information, or even execute arbitrary code if writable directories are accessible and contain executable scripts. This type of vulnerability is particularly dangerous in industrial control systems because it compromises not only the confidentiality and integrity of the device's local storage but also its availability by allowing potential corruption of critical operational parameters.
From an industry standard perspective, this issue aligns with CWE-22: Improper Limitation of a Pathname to a Restricted Directory. This weakness occurs when software does not sufficiently verify that user input is contained within expected directories before performing file operations. Furthermore, in the context of cyber attack frameworks like MITRE ATT&CK, this vulnerability facilitates techniques associated with Collection and Exfiltration over C2 channels if combined with other exploits, or more directly relates to Defense Evasion through Path Traversal. The ability to traverse outside restricted boundaries undermines the principle of least privilege and isolation that is essential for secure embedded system design.
The operational impact of this vulnerability extends beyond simple data leakage. In an industrial setting, the EasyIO FS32 serves as a controller or interface node within larger automation architectures. Compromising its file integrity can lead to unauthorized changes in control logic, modification of communication settings, or installation of persistent backdoors via uploaded malicious files if write permissions are misconfigured. This could result in physical process disruptions, safety hazards, or prolonged downtime for critical infrastructure operations. The lack of input validation means that any network-accessible service on the device handling file paths becomes a potential entry point for remote exploitation, provided the attacker has network access to the management interface or communication ports exposed by the firmware version affected.
Mitigation strategies must prioritize immediate patching and rigorous input sanitization. Johnson Controls released fixed versions starting with 3.0b63, which presumably implement proper validation checks to ensure that file paths remain within designated directories. Organizations operating vulnerable instances should upgrade their EasyIO FS32 devices to this patched version or later as the primary remediation step. In cases where immediate patching is not feasible due to operational constraints, temporary mitigations include restricting network access to the device’s management interfaces using firewalls and ACLs, disabling unnecessary file upload or read services if they are not required for normal operation, and implementing strict input validation rules at the application layer that reject any path containing traversal sequences. Regular security audits and penetration testing focused on path manipulation can help identify similar weaknesses in other components of the industrial control system ecosystem.