CVE-2026-12438 is a vulnerability in the WebView implementation of Google Chrome on Android prior to version 149.0.7827.155. It involves an inappropriate implementation that allows a remote attacker, who has already compromised the renderer process, to perform a sandbox escape by leveraging a crafted HTML page. This sandbox escape can lead to elevated privileges beyond the renderer process, potentially compromising the device's security. The vulnerability is classified under CWE-693 (Protection Mechanism Failure) and has a CVSS v3.1 base score of 8.3 (AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H), reflecting a high severity with network attack vector, high impact on confidentiality, integrity, and availability, and requiring user interaction.

Successful exploitation of this vulnerability can allow an attacker who has compromised the renderer process to escape the sandbox environment, leading to potential full device compromise. This impacts the confidentiality, integrity, and availability of the affected system. The vulnerability is critical in nature due to its ability to bypass security boundaries within the browser on Android devices.

Patch status is not yet confirmed — check the vendor advisory at https://chromereleases.googleblog.com/2026/06/stable-channel-update-for-desktop_01750511403.html for current remediation guidance. Users and administrators should monitor this advisory for updates and apply any official fixes once available. Until a patch is confirmed, limiting exposure by avoiding untrusted HTML content and minimizing renderer process compromise risk is advisable.