A vulnerability has been identified in SIMATIC WinCC OA UI for Android (All versions < V3.15.10), SIMATIC WinCC OA UI for iOS (All versions < V3.15.10). Insufficient limitation of CONTROL script capabilities could allow read and write access from one HMI project cache folder to other HMI project cache folders within the app's sandbox on the same mobile device. This includes HMI project cache folders of other configured WinCC OA servers. The security vulnerability could be exploited by an attacker who tricks an app user to connect to an attacker-controlled WinCC OA server. Successful exploitation requires user interaction and read/write access to the app's folder on a mobile device. The vulnerability could allow reading data from and writing data to the app's folder. At the time of advisory publication no public exploitation of this security vulnerability was known. Siemens confirms the security vulnerability and provides mitigations to resolve the security issue.