Advantech WebAccess/VPN < 1.1.5 Stored XSS via StandaloneVpnClientsController

Advisories

severity: medium
date: November 6, 2025
Affecting: WebAccess/VPN < 1.1.5
CVE: CVE-2025-34237
CWE: CWE-79 Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting')
CVSS: 6.3
CVSS V4 Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N
References: Advantech Advisory
Credit: Alex Williams from Pellera Technologies
Description: Advantech WebAccess/VPN versions prior to 1.1.5 contain a stored cross-site scripting (XSS) vulnerability via StandaloneVpnClientsController.addStandaloneVpnClientAction(). Insufficient validation or escaping of user-supplied input may allow an attacker to inject and execute arbitrary script in the context of a victim's browser.