A newly reported security flaw in Android—CVE-2025-26450—has caught the attention of security professionals. This vulnerability lies within the way the Android operating system handles input events via the IInputMethodSessionWrapper.java class. By failing to enforce proper permissions, Android devices are left open to an attack where malicious apps can inject fake keyboard or touch inputs to the system's default input method editor (IME). In plain terms: a malicious app could secretly "type" or "tap" on your behalf, gaining higher privileges on the device—*without you doing anything*.

Below, I'll walk you through a simple explanation, code snippets, references, and technical exploit details about this critical flaw.

What is CVE-2025-26450?

This vulnerability allows local escalation of privilege (EoP). It means an app running with normal permissions can exploit a missing permission check to send forged input events (like keyboard presses or touch), tricking the system or other apps. This can result in compromised user privacy, bypassed app restrictions, and even unauthorized access to sensitive features.

Critically, *no special permission* or user interaction is needed for the attacker—making this a silent yet potent threat.

Technical Details: Where's the Problem?

The root of the issue is in the Android system service class:
IInputMethodSessionWrapper.java
This Java class receives input events and passes them to the IME (keyboard service).

In the problematic method, onInputEvent(), the code fails to check if the event is actually coming from a trusted source with the proper permission.

Let’s examine a simplified snippet from the source

// IInputMethodSessionWrapper.java (simplified)
@Override
public void onInputEvent(InputEvent event, int seq) {
    // ... missing: permission checks ...
    mInputMethodSession.dispatchInputEvent(event, seq, mInputEventCallback);
}

Normally, before forwarding any event, there should be a check like

if (!hasPermission(BIND_INPUT_METHOD)) {
    throw new SecurityException("Permission denied");
}

But, in this case, the check is missing—so *any* app that can reach this API or call this binder interface can send inputs as if it were the keyboard or touch screen itself!

Exploit Example: Injecting Key Events from an App

A rogue app could send input events programmatically using an AIDL binding to the input method session, simulating real touches or key calls.

Here’s a rough sketch of how a malicious app could trigger this flaw (pseudo-code)

// Attacker code: send a "key press" without user action or special permissions
InputEvent fakeKeyEvent = new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_A);
// Connect to the InputMethodSession service (details skipped)
// Send the event
iInputMethodSession.onInputEvent(fakeKeyEvent, YOUR_SEQ_NUMBER);

The effect: Android’s default keyboard (IME) receives this as if you really pressed "A".

References

- Official CVE entry for CVE-2025-26450 *(pending update as of June 2024)*
- Android Open Source Project - IInputMethodSessionWrapper.java
- Google Android Security Advisories

Why This Matters

- No user interaction needed: Users don’t need to click or allow anything—the attack is silent.

Bypasses user sandbox: Standard permissions and sandboxing fail to block the attack.

- Potential for privilege escalation: Attackers can chain this with other vulnerabilities for even higher system access.

Update your device: Apply security updates provided by your device manufacturer.

- Review app permissions: Be cautious with unfamiliar apps, especially those requesting input or accessibility features.

Conclusion

CVE-2025-26450 is a classic example of how a single missing permission check can undermine an entire feature’s security. By exploiting the unprotected onInputEvent() handler, malicious apps can inject hidden key and motion events.

If you're a developer or a system administrator, it's crucial to stay on top of security patches for your devices. Users should ensure their phone is up-to-date, and avoid installing apps from untrusted sources.

Stay safe and updated!

*This breakdown is based on an early security research analysis. When official advisories and patches are released, follow up for the latest mitigations.*

References

- IInputMethodSessionWrapper.java source
- Google Android Security Bulletins

For the latest CVE details, check out the MITRE CVE Database.

Timeline

Published on: 09/04/2025 18:15:44 UTC
Last modified on: 09/08/2025 14:12:30 UTC