The vulnerability arises from the application's handling of the 'redirect' parameter used in the survey feature. Specifically, the application redirects users to a URL specified in the 'redirect' parameter without adequate validation or encoding. This oversight allows attackers to inject malicious JavaScript code as the redirect URL, which is executed in the user's browser upon completing the survey. Such vulnerabilities are particularly dangerous as they can lead to the theft of session cookies, account takeover, and other client-side attacks.

An attacker crafts a malicious URL containing a JavaScript payload in the 'redirect' parameter of the survey feature. The attacker then convinces a victim to click on this malicious link and complete the survey. Upon completion, the application redirects the user to the attacker-specified URL, causing the malicious JavaScript to execute in the context of the user's session. This could lead to the theft of session cookies or other sensitive information.

Users of the web application version 0.57.1 who interact with the survey feature and follow links containing a malicious 'redirect' parameter are vulnerable to this attack. This could potentially include a wide range of the application's user base, depending on the distribution and use of the malicious link.