CVE-2026-5754: Radware Alteon vADC XSS Vulnerability

CVE-2026-5754 Overview

A Reflected Cross-Site Scripting (XSS) vulnerability has been identified in Radware Alteon 34.5.4.0 vADC load-balancer. This vulnerability allows an attacker to inject malicious scripts into the website, potentially leading to unauthorized actions, data theft, session hijacking, or other malicious activities targeting users of the affected web interface.

Critical Impact

Attackers can execute arbitrary JavaScript code in the context of victim users' browsers, potentially stealing session cookies, credentials, or performing unauthorized actions on behalf of authenticated administrators.

Affected Products

• Radware Alteon 34.5.4.0 vADC Load Balancer

Discovery Timeline

• April 14, 2026 - CVE-2026-5754 published to NVD
• April 16, 2026 - Last updated in NVD database

Technical Details for CVE-2026-5754

Vulnerability Analysis

This reflected XSS vulnerability exists in the Radware Alteon vADC load-balancer web management interface. The vulnerability occurs when user-supplied input is reflected back to the browser without proper sanitization or encoding, allowing attackers to inject malicious JavaScript code.

Reflected XSS attacks require social engineering to trick a victim into clicking a specially crafted malicious link. When an authenticated administrator clicks such a link, the injected script executes in the context of their browser session with the same privileges as the legitimate user.

The network-accessible attack vector means this vulnerability can be exploited remotely, though user interaction is required for successful exploitation. While the vulnerability has changed scope (affecting resources beyond its original security context), it results in low-impact confidentiality and integrity breaches without affecting availability.

Root Cause

The root cause of this vulnerability is improper input validation and output encoding within the Radware Alteon web management interface. User-controlled input parameters are reflected in HTTP responses without adequate sanitization, allowing HTML and JavaScript injection. This failure to properly neutralize input before including it in web pages enables the execution of arbitrary client-side scripts.

Attack Vector

The attack vector is network-based, requiring an attacker to craft a malicious URL containing JavaScript payload and deliver it to a victim user. The attack flow typically involves:

1. Attacker identifies a vulnerable input field or URL parameter in the Alteon web interface
2. Attacker crafts a malicious URL containing embedded JavaScript code
3. Victim (typically an administrator) is tricked into clicking the malicious link
4. The vulnerable application reflects the malicious payload back without sanitization
5. The victim's browser executes the injected script with the user's session context

Successful exploitation could allow attackers to steal session tokens, capture credentials, redirect users to phishing sites, or perform administrative actions on behalf of the victim. For more information about the affected product, refer to the Radware Alteon Product Overview.

Detection Methods for CVE-2026-5754

Indicators of Compromise

• Unusual URL patterns in web server logs containing JavaScript code, HTML tags, or encoded script payloads
• Suspicious GET or POST requests to the Alteon management interface with parameters containing <script>, javascript:, or event handlers like onerror, onload
• Reports from users of unexpected browser behavior or pop-ups when accessing the management interface

Detection Strategies

• Deploy web application firewalls (WAF) with XSS detection rules to identify and block requests containing common XSS payloads
• Monitor HTTP request logs for suspicious patterns including URL-encoded script tags and JavaScript event handlers
• Implement Content Security Policy (CSP) headers and monitor for CSP violation reports indicating potential XSS attempts
• Use browser-based detection tools and security headers like X-XSS-Protection to identify reflected script execution

Monitoring Recommendations

• Enable detailed logging on the Radware Alteon management interface to capture all HTTP requests and responses
• Configure SIEM rules to alert on patterns indicative of XSS exploitation attempts targeting the load-balancer interface
• Regularly review access logs for anomalous requests, particularly those containing encoded characters or script-like content
• Monitor for unauthorized session activity that could indicate successful credential theft via XSS

How to Mitigate CVE-2026-5754

Immediate Actions Required

• Restrict access to the Radware Alteon web management interface to trusted networks and IP addresses only
• Implement additional authentication controls such as multi-factor authentication for administrative access
• Deploy a web application firewall with XSS filtering capabilities in front of the management interface
• Educate administrators about the risks of clicking untrusted links while authenticated to the management console

Patch Information

At the time of publication, no specific patch information is available from Radware. Administrators should monitor official Radware security advisories and the Radware Alteon Product Overview page for updates regarding security patches for version 34.5.4.0. Contact Radware support directly for guidance on available security updates or upgraded firmware versions that address this vulnerability.

Workarounds

• Limit network access to the Alteon management interface using firewall rules to allow only trusted administrator IP addresses
• Use a dedicated management network (out-of-band management) isolated from general user traffic
• Implement browser isolation for administrative tasks when accessing the management interface
• Consider using the CLI interface for administrative tasks instead of the web interface until a patch is available