CVE-2026-12438: Google Chrome RCE Vulnerability

CVE-2026-12438 Overview

CVE-2026-12438 is a sandbox escape vulnerability in the WebView component of Google Chrome on Android. The flaw stems from an inappropriate implementation that allows a remote attacker, who has already compromised the renderer process, to escape the Chrome sandbox through a crafted HTML page. Google has rated the Chromium security severity as Critical, while NVD assigns a CVSS 3.1 score of 8.3. The issue affects Google Chrome on Android prior to version 149.0.7827.155. Chromium maps this weakness to CWE-693: Protection Mechanism Failure, reflecting the bypass of the renderer-to-browser process isolation boundary.

Critical Impact
A compromised renderer can break out of the Chrome sandbox on Android via a crafted HTML page, granting attacker-controlled code access outside the renderer's restricted boundary.

Affected Products

Google Chrome for Android prior to 149.0.7827.155
Google Android (WebView component dependent on Chrome)
Embedded applications relying on Android System WebView built from affected Chromium versions

Discovery Timeline

2026-06-17 - CVE-2026-12438 published to NVD
2026-06-18 - Last updated in NVD database

Technical Details for CVE-2026-12438

Vulnerability Analysis

The vulnerability resides in the WebView implementation used by Chrome on Android. WebView embeds the Chromium rendering engine inside Android applications and enforces process isolation between the renderer and the browser process. An inappropriate implementation in this component weakens that boundary. An attacker who already controls the renderer process can leverage a crafted HTML page to perform actions outside the sandbox. This category of issue, classified under [CWE-693], represents a failure of a security control rather than a memory corruption primitive. Successful exploitation requires a prior renderer compromise, typically chained with a separate renderer bug, and user interaction with attacker-controlled web content.

Root Cause

The root cause is an inappropriate implementation within WebView that fails to fully enforce the sandbox protection mechanism between the renderer and host browser process on Android. Chromium tracks the underlying defect in Chromium Issue #516947912. Because the failure is in a protection boundary rather than a memory safety bug, the impact is escalation of attacker capability rather than direct code execution from a single primitive.

Attack Vector

Exploitation requires the attacker to first compromise the renderer process, then deliver a crafted HTML page that triggers the inappropriate WebView behavior. The attack is network-reachable and requires user interaction, such as visiting a malicious site or loading attacker-controlled content inside an Android app that embeds WebView. The scope is changed because the breach in the renderer-process security boundary affects resources managed by the host browser process. The vulnerability does not include a publicly available proof of concept, and no in-the-wild exploitation has been confirmed.

No verified public exploit code is available for CVE-2026-12438. Technical detail is restricted to the Google Chrome Stable Channel Update and the referenced Chromium issue tracker entry, both of which remain access-restricted at the time of publication.

Detection Methods for CVE-2026-12438

Indicators of Compromise

Android devices or apps running Chrome or System WebView versions prior to 149.0.7827.155
Unexpected child processes or privileged file system access originating from a WebView-hosting application
Outbound connections from WebView processes to untrusted domains shortly after rendering attacker-supplied HTML

Detection Strategies

Inventory Chrome and Android System WebView versions across managed Android devices using MDM or EDR telemetry.
Flag processes spawned by com.google.android.webview or com.android.chrome that perform actions inconsistent with renderer sandbox restrictions.
Correlate browsing telemetry with process behavior to identify renderer-to-browser boundary anomalies following HTML page loads.

Monitoring Recommendations

Continuously monitor mobile fleet patch posture for Chrome on Android against version 149.0.7827.155 and later.
Alert on Android applications embedding outdated WebView versions, particularly those handling untrusted web content.
Track network connections from WebView-hosting apps to newly observed or low-reputation domains.

How to Mitigate CVE-2026-12438

Immediate Actions Required

Update Google Chrome on Android to version 149.0.7827.155 or later through the Google Play Store.
Update Android System WebView to the matching patched build to remediate apps that embed WebView.
Restrict installation of Android applications that load untrusted remote HTML in WebView until patching is verified.

Patch Information

Google addressed CVE-2026-12438 in Chrome for Android version 149.0.7827.155. Refer to the Google Chrome Stable Channel Update for release notes. The fix is delivered through standard Chrome and Android System WebView update channels in Google Play.

Workarounds

Avoid loading untrusted or attacker-controllable HTML content in WebView-based applications until updates are applied.
Enforce mobile device management policies that require current Chrome and System WebView versions before granting access to corporate resources.
Disable or sandbox third-party Android applications known to render arbitrary remote web content in WebView.

bash

# Verify installed Chrome version on a managed Android device via adb
adb shell dumpsys package com.android.chrome | grep versionName

# Verify installed Android System WebView version
adb shell dumpsys package com.google.android.webview | grep versionName