TL;DR This vulnerability affects Kirby sites that use the URL field in any blueprint. A successful attack commonly requires knowledge of the content structure by the attacker as well as social engineering of a user with access to the Panel. The attack cannot be automated. The vulnerability is also limited to self-XSS and cannot directly affect other users or visitors of the site. Introduction Cross-site scripting (XSS) is a type of vulnerability that allows to execute any kind of JavaScript code inside the Panel session of the same or other users. In the Panel, a harmful script can for example trigger requests to Kirby's API with the permissions of the victim. Self cross-site scripting (self-XSS, also called reflected XSS) typically involves a user inadvertently executing malicious code within their own context, often through social engineering techniques. This can occur when a user is tricked into pasting and executing malicious JavaScript code into the browser's developer console, address bar or form fields. Such vulnerabilities are critical as they allow attackers to gain access to the system or to escalate their privileges if they get access to the Panel session of an admin user. Depending on your site, other JavaScript-powered attacks are possible. Impact The URL field allows users to open the entered link in a new tab by clicking the link icon inside the field. This can be used to quickly verify whether the entered URL is functional and correct. In affected versions,…Read More