An issue was discovered in KaiOS 2.5 and 2.5.1. The pre-installed File Manager application is vulnerable to HTML and JavaScript injection attacks. An attacker can send a file via email to the victim that will inject HTML into the File Manager application (assuming the victim chooses to download the email attachment). At a bare minimum, this allows an attacker to take control over the File Manager application's UI (e.g., display a malicious prompt to the user asking them to re-enter credentials such as their KaiOS credentials to continue using the application) and also allows an attacker to abuse any of the privileges available to the mobile application.