CVE-2026-63352 in Siemens
Summary
by MITRE • 10/13/2026
Affected devices do not properly sanitize calculated signal data contained in imported CSV trace files before rendering it on the Trace page.
This could allow an attacker to social engineer an authorized user who holds the function right “Read diagnostics” into importing a specially crafted trace file. Successful exploitation could allow attacker-controlled JavaScript to execute in the user’s browser session and perform PLC operations through the web server within the scope of the user’s authorization.
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Analysis
by VulDB Data Team • 10/13/2026
The vulnerability described constitutes a critical Cross-Site Scripting (XSS) flaw rooted in insufficient input validation and sanitization mechanisms within the device's web interface. Specifically, the system fails to properly sanitize calculated signal data embedded in imported CSV trace files before rendering them on the Trace page. This technical deficiency allows malicious actors to inject executable JavaScript code into the application context by disguising it as legitimate diagnostic data within a structured file format. The core of the issue lies in the lack of rigorous output encoding or content security policy enforcement when processing user-supplied input, which is a classic manifestation of CWE-79: Improper Neutralization of Input During Web Page Generation. This failure to neutralize special characters allows scripts that are intended for execution rather than display to be interpreted by the browser's JavaScript engine.
The operational impact of this vulnerability is severe due to its potential for privilege escalation and lateral movement within industrial control systems. An attacker cannot exploit this flaw directly through automated means; instead, it requires a social engineering component where they trick an authorized user with Read diagnostics privileges into importing a specially crafted CSV file. Once the victim imports the malicious trace file, the embedded JavaScript executes in the context of their active browser session. Because the script runs within the scope of the user's authorization, it inherits those permissions, allowing the attacker to perform PLC operations through the web server as if they were the legitimate operator. This capability effectively bypasses authentication controls and can lead to unauthorized manipulation of industrial processes, posing significant risks to operational technology environments where safety and integrity are paramount.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1059: Command and Scripting Interpreter, specifically JavaScript execution within a browser environment. The attack vector leverages the trust relationship between the user's session and the web application to execute arbitrary commands on behalf of the privileged account. This scenario highlights the danger of combining client-side vulnerabilities with high-privilege roles in industrial settings. The ability to perform PLC operations remotely via a compromised browser session means that an attacker could potentially alter process parameters, halt production lines, or cause physical damage depending on the specific capabilities exposed by the web server interface.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. Immediate actions should include implementing strict input validation for all imported CSV files, ensuring that only expected data types are accepted and any potentially executable content is stripped out before processing. Output encoding must be enforced rigorously to ensure that any dynamic content rendered in the Trace page is treated as text rather than code. Additionally, deploying a Content Security Policy (CSP) header can significantly reduce the impact of successful XSS attacks by restricting the sources from which scripts are allowed to load and execute. Long-term solutions involve adopting secure coding practices such as parameterized queries for data handling and conducting regular security audits focused on web application vulnerabilities in operational technology systems.