CVE-2026-82776 in Integrated Type CPS-PC341
Summary
by MITRE • 09/14/2026
Cross-site scripting vulnerability exists in CONPROSYS PAC Series. If this vulnerability is exploited, an arbitrary script may be executed on a logged-in user's web browser.
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Analysis
by VulDB Data Team • 09/14/2026
The identified cross-site scripting (XSS) vulnerability within the CONPROSYS Programmable Automation Controller series represents a significant security risk to industrial control systems that rely on web-based interfaces for monitoring and configuration. This flaw allows an attacker to inject malicious client-side scripts into pages viewed by authenticated users, leveraging the trust relationship between the user's browser and the application interface. The presence of this vulnerability indicates insufficient input validation or output encoding mechanisms within the web server components responsible for rendering dynamic content based on user-supplied data.
From a technical perspective, the core issue lies in the failure to properly sanitize special characters such as angle brackets, quotes, and ampersands before they are processed by the browser's HTML parser. When an attacker crafts a malicious payload containing JavaScript code and submits it through vulnerable input fields or URL parameters, the application reflects this data back into the response without adequate encoding. Consequently, when another user with valid credentials accesses the affected page, their browser executes the injected script as if it originated from the trusted PAC system. This mechanism bypasses standard security controls because the execution context is considered legitimate by the browser's same-origin policy.
The operational impact of this vulnerability extends beyond simple defacement or session hijacking in typical web applications; in an industrial environment, it poses a direct threat to process safety and availability. An attacker could exploit this flaw to steal administrative cookies or authentication tokens, thereby gaining unauthorized access to sensitive system configurations. Furthermore, the malicious script can interact with the application's Document Object Model to manipulate interface elements, potentially leading to misleading operational data being displayed to operators or triggering unintended actions within the control logic if the web interface has write capabilities. This compromises both confidentiality and integrity of the industrial process management layer.
This vulnerability aligns closely with CWE-79, which classifies improper neutralization of input during web page generation as a cross-site scripting flaw. In terms of tactical mapping to the MITRE ATT&CK framework for Industrial Control Systems, this exploit falls under T1053, specifically related to scheduled tasks or commands that can be manipulated via interface vulnerabilities, and more broadly under techniques involving client-side code injection used for credential harvesting or session manipulation such as T1589. The ability to execute arbitrary scripts effectively grants the attacker a foothold within the trusted network segment where the PAC resides, facilitating further lateral movement if additional services are exposed through the same web server infrastructure.
Mitigation strategies must prioritize immediate remediation of the input validation logic on the affected firmware version. Developers should implement strict output encoding for all user-supplied data rendered in HTML contexts to ensure that script tags and event handlers are treated as plain text rather than executable code. Additionally, deploying a Web Application Firewall can provide an interim layer of defense by filtering out known malicious payloads before they reach the application server. For long-term resilience, adopting Content Security Policy headers can restrict the sources from which scripts are allowed to load, thereby limiting the impact even if injection occurs. Regular security assessments and penetration testing focused on web interface components are essential to identify similar flaws across other modules of the CONPROSYS ecosystem.