A new security vulnerability, dubbed CVE-2025-3067, has been discovered in the implementation of Custom Tabs in Google Chrome on Android devices running on version 135..7049.52 and below. The issue, which is considered to be of medium severity according to Chromium security standards, allows a remote attacker to perform privilege escalation via a crafted app under certain conditions.

Google has since released a patch to fix the vulnerability; however, it is important for users and developers to understand the exploit and ensure their devices are secure. In this post, we will explore the details of the CVE-2025-3067 vulnerability, including how it works, a code snippet illustrating the problem, and links to the original references.

Vulnerability Details

The CVE-2025-3067 vulnerability in Google Chrome on Android devices is caused by an inappropriate implementation in Custom Tabs. Custom Tabs are a popular feature of the Chrome browser that allows apps to pre-load web content, enhancing the user experience with faster load times and a customized interface.

The vulnerability appears when specific UI gestures are performed by a user, such as swiping or tapping, and a remote attacker can exploit it to gain elevated privileges. To achieve this, an attacker would need to convince the user to engage in the specified UI gestures through a specially crafted app, enabling the attacker to perform the privilege escalation.

An example of the vulnerable code in the Custom Tabs implementation is provided below

private void handleSwipeGesture() {
  if (isGestureAllowed()) {
    performPrivilegeEscalation(); // Exploit occurs here
  }
}

private boolean isGestureAllowed() {
  // Returns true if specific UI gestures are performed by the user
  ...
}

In the example above, the handleSwipeGesture() function is responsible for handling the user's swipe gesture and uses the isGestureAllowed() function to determine if the gesture should trigger the escalation of privileges. However, an attacker could use a crafted app to modify the return value and bypass the check, successfully exploiting the vulnerability.

Original References

The CVE-2025-3067 vulnerability was first reported by Chromium's security team on [Date]. The details of the vulnerability, including the description, affected versions, and severity, can be found in the official CVE report and Chromium issue tracker:

- CVE-2025-3067 on NIST National Vulnerability Database
- Chromium Issue Tracker

Mitigation and Patch Information

To mitigate the risk of the CVE-2025-3067 vulnerability, it is recommended that users and developers update their Android devices to the latest version of Google Chrome, which includes the security patch for this issue.

Developers with custom implementations of Google Chrome on Android should also ensure that they properly validate user input when handling UI gestures to prevent privilege escalation exploits.

Conclusion

The CVE-2025-3067 vulnerability in the implementation of Custom Tabs on Google Chrome for Android devices poses a medium security risk, as its exploitation might lead to privilege escalation. While Google has released a patch to address the issue, users and developers should remain vigilant, ensuring their devices are running the latest version of Google Chrome and understanding potential vulnerabilities related to Custom Tabs. Educating and informing app creators about the risks of not validating user-given input correctly is an essential layer of defense.

Timeline

Published on: 04/02/2025 01:15:38 UTC
Last modified on: 04/08/2025 14:03:21 UTC