CVE-2026-45452 in UniStream Pro
Summary
by MITRE • 10/15/2026
Use of Externally-Controlled format string vulnerability in Unitronics Unitronics UniStream Pro/UniLogic.
This issue affects Unitronics UniStream Pro/UniLogic: Unitronics UniStream Pro versions only (B10 / C10) – UniLogic versions prior to 1.41.329.
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Analysis
by VulDB Data Team • 10/15/2026
The vulnerability identified as a use of externally-controlled format string in the Unitronics UniStream Pro and UniLogic software environment represents a critical security flaw within industrial control systems. This specific issue impacts units running firmware version B10 or C10, specifically when utilizing UniLogic versions prior to 1.41.329. Format string vulnerabilities arise when an application fails to properly sanitize user-supplied input before passing it as the format argument in functions such as printf, fprintf, sprintf, snprintf, syslog, and similar variants that interpret special characters within strings. In this context, an attacker who can inject maliciously crafted data into a field processed by these formatting routines gains significant control over how the software interprets memory operations during runtime execution.
From a technical perspective, the core flaw lies in the improper handling of input validation mechanisms within the UniLogic programming environment or its associated communication protocols. When external inputs are accepted without rigorous type checking and sanitization, an adversary can embed format specifiers such as %x, %n, or %s directly into data packets intended for processing by the controller's logic engine. These specifiers instruct the underlying C library functions to read from or write to arbitrary locations in memory based on values found on the stack rather than using fixed buffer addresses. This behavior deviates significantly from secure coding standards which mandate that format strings should always be literal constants, with user data passed as subsequent arguments to ensure safe interpretation and prevent unintended side effects during string formatting operations.
The operational impact of exploiting this vulnerability is severe and multifaceted, potentially leading to complete compromise of the industrial control system's integrity and availability. Successful exploitation allows an attacker to achieve arbitrary code execution by leveraging write-what-where capabilities inherent in format specifiers like %n, which writes a value to a specified memory address. This capability can be used to overwrite function pointers or return addresses on the stack, thereby redirecting program flow to shellcode injected into the process memory space. Furthermore, even without achieving code execution, reading from arbitrary memory locations via %x or %p specifiers enables information disclosure, allowing attackers to leak sensitive data such as encryption keys, session tokens, or internal system states that could facilitate further attacks against the network infrastructure supporting critical industrial processes.
This vulnerability aligns closely with Common Weakness Enumeration identifier CWE-134, which categorizes use of externally-controlled format string as a distinct class of input validation errors. The exploitation technique maps directly to MITRE ATT&CK framework techniques related to command and control or defense evasion, specifically those involving memory manipulation and indirect execution paths. In industrial environments where UniLogic is deployed for managing PLCs and HMI interfaces, such vulnerabilities pose existential risks because they bypass traditional perimeter defenses by operating within the trusted application layer itself. Attackers targeting these systems often seek to disrupt physical processes, steal intellectual property related to manufacturing recipes, or establish persistent backdoors for long-term espionage activities against critical infrastructure sectors including energy, water treatment, and transportation networks.
Mitigation strategies must prioritize immediate software updates as the primary defense mechanism. Organizations utilizing Unitronics UniStream Pro hardware should upgrade their UniLogic development environment to version 1.41.329 or later, where this specific format string handling flaw has been addressed through improved input validation routines and stricter enforcement of safe formatting practices within the compiled logic code. In addition to patching, network segmentation plays a crucial role in limiting exposure by isolating programming stations and HMI devices from general corporate networks using firewalls and VLANs configured according to IEC 62443 standards for industrial automation and control systems security. Access controls should be strictly enforced so that only authorized personnel with verified credentials can upload new logic programs or modify existing configurations, thereby reducing the attack surface available to potential intruders attempting to inject malicious format strings through legitimate administrative interfaces.
Security monitoring tools deployed within the OT network segment should be configured to detect anomalous patterns indicative of format string exploitation attempts, such as unusual spikes in memory access violations or unexpected changes in process variable values that correlate with specific input sequences. Regular vulnerability assessments and penetration testing conducted by qualified professionals familiar with industrial protocols like Modbus TCP or Ethernet/IP can help identify residual weaknesses before they are exploited in the wild. Developers integrating custom scripts or third-party libraries into UniLogic projects must also adhere to secure coding guidelines, ensuring that all external inputs undergo rigorous validation checks for length, type, and character set restrictions prior to being passed to any formatting functions within the application logic.