CVE-2026-57816 describes a reflected cross-site scripting vulnerability in Funnel Builder by FunnelKit, affecting versions through 3.15.0.8. The issue is caused by improper neutralization of input during web page generation, which allows an attacker to inject and execute malicious scripts in the victim's browser. The CVSS 3.1 base score is 7.1, indicating a high severity with network attack vector, low attack complexity, no privileges required, user interaction required, and impacts on confidentiality, integrity, and availability. No vendor advisory or patch information is available at this time.

Successful exploitation of this vulnerability can allow an attacker to execute arbitrary scripts in the context of the victim's browser session, potentially leading to theft of sensitive information, session hijacking, or other malicious actions impacting confidentiality, integrity, and availability to a limited extent. The reflected nature requires user interaction to trigger the attack.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, users should exercise caution with untrusted input and consider implementing web application firewall (WAF) rules to detect and block reflected XSS attempts. Monitor vendor channels for updates and patches.