CVE-2025-26444 - How a System Logic Error in VoiceInteractionManagerService Can Lead to Assistant Privilege Escalation in Android

In the ever-evolving world of Android security, the discovery of a bug in critical system services can have major impacts. CVE-2025-26444 is one such flaw, affecting the VoiceInteractionManagerService component. This vulnerability allows a local attacker (or any app running on the device) to trigger an unintended privilege escalation, all thanks to a subtle logic error in how Android handles forcibly stopped assistant apps. In this article, we’ll break down what exactly is happening, provide code snippets showing the root cause, and explain how an exploit could work in the real world.

What is the VoiceInteractionManagerService?

The VoiceInteractionManagerService is a system-level service that manages Android's voice assistant functionality. It controls which app is set as the active assistant (like Google Assistant or a third-party assistant) and manages their running state and permissions.

The Bug: onHandleForceStop Logic Error

The vulnerable code lives inside VoiceInteractionManagerService.java, specifically in the onHandleForceStop method. This function is supposed to handle the case where an assistant app is force-stopped (for example, by the user or the system). The intention is to ensure user experience stays smooth and the correct assistant remains active.

However, due to a logic bug, the system can accidentally revert to the default assistant application, granting it the ROLE_ASSISTANT—even if the user had selected a different assistant. Worse, this reversion happens *automatically*, with no user consent, and grants critical permissions to the default assistant app.

Below is a simplified code snippet showing what’s going on

public void onHandleForceStop(String packageName) {
    if (packageName.equals(currentAssistantPackage)) {
        revertToDefaultAssistant();
    }
    // ...
}

private void revertToDefaultAssistant() {
    setAssistant(defaultAssistantPackage); // <- logic bug: grants default role without user confirmation!
}

Key Point:
- If a user-preferred assistant is force-stopped, the system unconditionally grants the default assistant app the critical ROLE_ASSISTANT role.

No User Interaction Needed:

Any app on the device can trigger a force-stop intent for the current assistant app. The system then silently switches to the default assistant and gives it privileged permissions.

Automatic Permission Grant:

The default assistant app (often the pre-installed system assistant) is given the ROLE_ASSISTANT without extra confirmation or execution privileges.

Violation of User Choice:

Users who selected an alternative assistant app may find themselves reverted to the default, without consent or warning.

Force-Stop the Assistant:

Use the ActivityManager's forceStopPackage() or trigger a crash via unusual input (if allowed) to force-stop the net assistant.

System Reversion:

The system, via the buggy onHandleForceStop, automatically assigns the ROLE_ASSISTANT to the default assistant app.

Privilege Escalation:

The default assistant now has extra capabilities, including reading all user queries, voice commands, and access to personal data. The attacker app doesn’t need to interact with the user at all.

Example (pseudo-code)

ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
am.forceStopPackage(currentAssistantPackage); // Triggers the bug!

Who Is Affected?

Any Android device vendor or ROM that uses the flawed logic in VoiceInteractionManagerService.java is potentially affected. The bug lives in AOSP (Android Open Source Project) base code, so any fork that hasn’t patched it is at risk.

How to Mitigate

- Vendors: Patch your Android builds by adding proper authorization checks before granting the assistant role.

Original References

- Android Security Bulletin (June 2025)
- Code Review: VoiceInteractionManagerService.java changes
- What Is the Android Assistant Role?

Conclusion

CVE-2025-26444 is a good example of how even seemingly small logic mistakes deep in system code can have serious privilege and privacy impacts. The fix is all about respecting user choice and making sure roles/permissions are not auto-assigned without clear consent. As always, keep your devices updated and stay aware of newly disclosed vulnerabilities.

*If you want more deep dives and exclusive analysis of Android system bugs, stay tuned!*

Timeline

Published on: 09/04/2025 18:15:43 UTC
Last modified on: 09/08/2025 14:13:37 UTC