An issue was discovered in KaiOS 2.5 and 2.5.1. The pre-installed Contacts application is vulnerable to HTML and JavaScript injection attacks. An attacker can send a vCard file to the victim that will inject HTML into the Contacts application (assuming the victim chooses to import the file). At a bare minimum, this allows an attacker to take control over the Contacts 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.

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.

An issue was discovered in KaiOS 1.0, 2.5, and 2.5.1. The pre-installed Radio application is vulnerable to HTML and JavaScript injection attacks. A local attacker can inject arbitrary HTML into the Radio application. At a bare minimum, this allows an attacker to take control over the Radio 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.

An issue was discovered in KaiOS 1.0, 2.5, and 2.5.12.5. The pre-installed Email application is vulnerable to HTML and JavaScript injection attacks. An attacker can send a specially crafted email to the victim that will inject HTML into the email application's UI as soon as the email is opened. At a bare minimum, this allows an attacker to take control over the Email application's UI (e.g., display a malicious prompt to the user asking them to re-enter their email credentials) and also allows an attacker to abuse any of the privileges available to the mobile application.