Potential XSS on personal menu navigation

Vulnerability

The BlueSpiceUserSidebar extension in BlueSpice 4.x contains a cross-site scripting (XSS) vulnerability. Users with regular accounts and edit permissions can inject arbitrary HTML into the personal menu navigation by editing a menu item. This affects both the attacker's own navigation and that of other users. The issue is present in all versions prior to BlueSpice 4.2.1. [1]

Exploitation

An attacker must have an authenticated account with edit permissions on the BlueSpice instance. By editing a menu item in the personal navigation, the attacker can inject malicious HTML or JavaScript. The injected content is then rendered in the personal menu navigation of the attacker and other users when they view the page. No additional user interaction is required beyond the victim viewing the affected menu. [1]

Impact

Successful exploitation allows the attacker to execute arbitrary HTML and JavaScript in the context of other users' browsers. This can lead to session hijacking, credential theft, or other client-side attacks. The attacker gains the ability to perform targeted attacks against other users, potentially compromising their accounts or data. [1]

Mitigation

The vulnerability is fixed in BlueSpice version 4.2.1. Users should upgrade to this version or later. No workarounds are documented in the advisory. The issue was discovered during an internal security audit. [1]