Radware Alteon vADC reflected XSS via login parameter
Radware Alteon 34.5.4.0 vADC load-balancer contains a reflected XSS vulnerability in the /protected/login route's ReturnTo parameter enabling arbitrary JavaScript execution.
Sourcekb.cert.org — open the original
What to check
- Applies to
- The 1 CVE named below. Whether you run an affected version is not assessed: check the versions the source lists.
- Exploitation
- No exploitation in the wild and no public exploit is recorded for the CVEs named.
A reflected Cross-Site Scripting (XSS) vulnerability (CVE-2026-5754) affects Radware Alteon version 34.5.4.0 vADC load-balancer. The vulnerability exists in the ReturnTo parameter of the /protected/login route, where insufficient input sanitization allows attackers to inject malicious scripts. When users request resources that redirect to Microsoft SAML login pages, the load-balancer fails to sanitize the ReturnTo parameter, enabling payload injection that executes in victim browsers.
The attack chain is straightforward: an attacker crafts a malicious link containing XSS payload in the ReturnTo parameter, the victim clicks the link and is redirected to the login page, and the load-balancer reflects the malicious parameter back, triggering JavaScript execution. This enables session cookie theft, unauthorized actions on behalf of victims, phishing attacks, and damage to organizational reputation.
Radware has acknowledged the vulnerability in their customer portal and indicated a patch would be included in version 34.5.7.0, expected March 31, 2026, though release confirmation is unclear. CERT/CC was unable to reach the vendor for coordination. Organizations should implement input validation and encoding controls as interim mitigations.
Mentioned in this report
Source reporting: https://kb.cert.org/vuls/id/890999
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