Android bug lets Gemini send messages without unlocking your phone
Your locked phone wasn't as locked as you thought.
Image by Getty/Thomas Trutschel
- Google is fixing an Android 16 bug that lets Gemini send SMS and WhatsApp messages from locked phones.
- The flaw uses a multi-touch gesture to bypass PIN checks when Gemini hands users from the lock screen to apps.
- Attackers need physical access, but researchers warn phone thefts could make the bug useful for scams or extortion.
- Users can reduce risk by disabling Gemini use without unlocking or blocking calls and messages from the lock screen.
Key Takeaways by nexos.ai, reviewed by Cybernews staff.
We all love convenience when it comes to technology – but even a strong PIN might not be enough to protect your phone if there is a simple software bug. Google is rolling out a fix for a vulnerability that allows virtually anyone with physical access to an Android 16 device to use Gemini to send SMS and WhatsApp messages from your phone. No PIN required.
The Register says it has received multiple reports of users bypassing device authentication on Android 16 devices that allow access to Gemini from the lock screen.
The exploit relies on a specific multi-touch gesture. Imagine you've disabled Gemini's access to Messages. If someone picks up your phone and asks Gemini to send an SMS, it won’t do it because it no longer has permission.
Instead, it would say “You can do that on the Apps page” and prompt the user to open the Messages app. Tapping “Continue” would open a screen locked behind a PIN. So far, everything is working as intended.
The bug happens when a user presses “Continue” simultaneously with Gemini’s “Add attachment” button. Instead of enforcing the PIN check, Android then accidentally lets unauthenticated users send messages via Gemini directly.
From there, an attacker can also restore Gemini's access to other apps, even if they were intentionally disabled. Any permission requested by Gemini can simply be granted using the same technique.
Besides sending messages, an attacker may view or delete Gemini chat history, modify some security settings, and exfiltrate data without ever needing a PIN, according to Mallory.
The bug was reportedly reproduced on a fully patched Pixel 6a, suggesting it affects devices running the latest available security updates.
Researchers believe the issue comes from Gemini's Deep Research and lock-screen app-handoff behavior, where authentication checks can fail when Gemini transitions from the lock-screen interface to full app access.
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Exploiting the bug in the wild requires physical access to a device. Nonetheless, researchers highlight that the rise in phone thefts could make this bug particularly attractive to attackers, who could then try to extort money by sending fake kidnapping or phishing messages to victims' contacts.
A Google spokesperson told the Register that a fix has already been implemented and is scheduled for deployment this week.
In the meantime, you can protect your phone by fully turning off "Use Gemini without unlocking" or disabling "Make calls and send messages without unlocking."
