AgentFlow, developed by Flowring, contains a reflected cross‑site scripting flaw that permits unauthenticated remote attackers to execute arbitrary JavaScript code in a user’s browser. Attackers can craft malicious URLs and deliver them through phishing attacks; when a user opens the link, the script runs within their browser. The vulnerability arises from insufficient input validation during the handling of query parameters that are echoed in the HTTP response (CWE‑79).

The affected product is Flowring’s AgentFlow. Installations using the default build prior to version 4.0.0.1878.877 are vulnerable; upgrading to that version or any later release removes the flaw.

The CVSS score of 5.1 indicates moderate risk, and the EPSS score of less than 1% suggests a very low probability of exploitation. This vulnerability is not listed in CISA’s KEV catalog. The most likely attack vector is phishing, where an attacker sends a user a link that, when clicked, triggers the reflected script. No authentication or elevated privileges are required to exploit the vulnerability.