CVE-2026-73700 in Fabric Composer
Summary
by MITRE • 09/01/2026
A vulnerability in the web-based management interface of HPE Networking Fabric Composer could allow an authenticated low privilege operator user to conduct a stored cross-site scripting (XSS) attack against an administrative user of the interface. A successful exploit could allow an attacker to execute arbitrary script code in a victim's browser in the context of the affected interface.
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Analysis
by VulDB Data Team • 09/01/2026
The vulnerability identified within the HPE Networking Fabric Composer web-based management interface represents a significant security risk due to its potential for privilege escalation through social engineering and cross-site scripting techniques. Specifically, this flaw allows an authenticated user with low-privilege operator access to inject malicious script code into the application's data stores. This stored cross-site scripting (XSS) vulnerability arises from insufficient validation or sanitization of user-supplied input fields that are subsequently rendered in the administrative interface without proper encoding. Unlike reflected XSS attacks, which require tricking a victim into clicking a crafted link, this stored variant persists on the server side, meaning the malicious payload is executed automatically whenever an administrator views the compromised page, thereby increasing the likelihood of successful exploitation and broadening the attack surface significantly.
From a technical perspective, the core issue lies in the application's failure to properly neutralize special characters that have significance within HTML or JavaScript contexts before storing them for later retrieval by administrative users. When an operator user submits data containing executable script tags or event handlers, the system accepts this input and stores it without adequate filtering. Consequently, when a higher-privileged administrator accesses the management interface to review network configurations or logs where this malicious content was injected, their browser interprets the stored scripts as legitimate code belonging to the application domain. This context switching allows the attacker's script to operate with the same privileges as the administrative user, effectively bypassing role-based access controls that were designed to restrict low-privilege users from performing sensitive management tasks.
The operational impact of this vulnerability is severe, primarily because it facilitates a lateral movement or privilege escalation scenario within the network infrastructure management plane. An attacker who has gained initial foothold with operator-level credentials can leverage this flaw to execute arbitrary JavaScript code in the context of an administrative session. This capability enables the theft of sensitive data such as authentication cookies, session tokens, and configuration details that are typically accessible only to administrators. Furthermore, the malicious script could perform actions on behalf of the administrator, including modifying network configurations, disabling security policies, or deploying unauthorized changes to the fabric composition. In a critical infrastructure environment, such unauthorized modifications can lead to service disruption, loss of integrity in network topology management, and potential compromise of downstream systems connected through the managed fabric.
This vulnerability aligns with Common Weakness Enumeration (CWE) ID 79, which classifies Improper Neutralization of Input During Web Page Generation known as Cross-site Scripting. Specifically, it falls under CWE-83 for Stored XSS where the malicious script is saved on a target server and executed when other users access the affected page. In terms of offensive security frameworks, this exploit maps to MITRE ATT&CK technique T1059 Command and Scripting Interpreter, specifically JavaScript execution within a browser context, as well as T1213 Data from Information Repositories if used for data exfiltration. The attack vector also relates to privilege escalation strategies where an attacker leverages application logic flaws to gain higher-level access than initially granted by the system's authentication mechanism.
Mitigation of this vulnerability requires immediate attention to input validation and output encoding practices within the Fabric Composer software. Developers must implement strict allow-list based filtering for all user inputs, ensuring that only expected data formats are accepted while rejecting any potentially executable content such as script tags, event handlers, or JavaScript URIs. Additionally, context-sensitive output encoding should be applied whenever data is rendered in HTML pages to prevent browsers from interpreting stored strings as code. For organizations currently running affected versions of HPE Networking Fabric Composer, applying the vendor-provided security patch is the primary remediation step. In the interim, network segmentation strategies can help limit lateral movement by restricting operator users' access to administrative interfaces and enforcing multi-factor authentication for high-privilege accounts to reduce the impact if session hijacking occurs through cookie theft. Regular audits of user inputs and continuous monitoring for anomalous script execution in management consoles are also recommended defensive measures to detect potential exploitation attempts early.