CVE-2026-55730 in LWEB-802
Summary
by MITRE • 07/24/2026
Reflected Cross-Site Scripting (CWE-79) in LWEB802 in Loytec LWEB-802 before 5.0.8 on all platforms allows an unauthenticated remote attacker to execute arbitrary JavaScript in a victim's browser and perform actions with the victim's privileges via a crafted link containing a malicious `project` or `mspParams` parameter.
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Analysis
by VulDB Data Team • 07/24/2026
This vulnerability represents a classic reflected cross-site scripting flaw that affects the Loytec LWEB-802 web application firmware version 5.0.7 and earlier. The vulnerability manifests through improper input validation and output encoding mechanisms within the web interface, specifically when processing user-supplied parameters in the project or mspParams fields. The weakness allows an attacker to inject malicious JavaScript code that gets executed in the context of a victim's browser session, creating a persistent security risk for all users interacting with the affected system.
The technical implementation of this vulnerability stems from CWE-79, which categorizes cross-site scripting attacks as a result of insufficient input validation and output sanitization. When an attacker crafts a malicious URL containing specially formatted project or mspParams parameters, the web application fails to properly sanitize these inputs before reflecting them back to the user's browser. This creates an execution environment where attacker-controlled JavaScript code can run within the victim's browser context, potentially leading to session hijacking, credential theft, or other malicious activities that leverage the victim's authenticated privileges.
The operational impact of this vulnerability extends beyond simple script execution, as it enables a range of sophisticated attacks that align with multiple techniques documented in the ATT&CK framework under the web application attack surface. An attacker could exploit this vulnerability to perform session manipulation, steal cookies, redirect users to malicious sites, or even establish persistent backdoors within the network infrastructure managed by the Loytec device. The unauthenticated nature of the attack means that any user who clicks on the malicious link becomes a potential victim, regardless of their authentication status or administrative privileges.
The security implications are particularly concerning given that this vulnerability affects all platforms supported by the LWEB-802 firmware, indicating a fundamental flaw in the application's input handling architecture rather than a platform-specific issue. This type of vulnerability commonly leads to privilege escalation scenarios where attackers can leverage the reflected script execution to perform actions that should only be available to authenticated administrators. Organizations using this device face significant risk of unauthorized access and potential network compromise, especially in environments where the device serves as a gateway or management interface for critical infrastructure components.
Mitigation strategies should focus on immediate firmware updates to version 5.0.8 or later, which would address the input validation deficiencies that enable this attack vector. Network segmentation and web application firewalls can provide additional protection layers by filtering malicious traffic before it reaches the vulnerable application. Input sanitization mechanisms should be implemented at multiple levels including parameter validation, output encoding, and content security policy enforcement to prevent similar vulnerabilities from emerging in other components of the system architecture. Security monitoring should also include detection of suspicious URL patterns and unusual parameter combinations that might indicate attempted exploitation of reflected XSS vulnerabilities.