CVE-2026-13866 Overview
CVE-2026-13866 is a site isolation bypass vulnerability affecting Google Chrome on Android before version 150.0.7871.47. The flaw exists in the Input component and results from an inappropriate implementation classified under [CWE-20: Improper Input Validation]. A remote attacker who has already compromised the renderer process can serve a crafted HTML page that circumvents site isolation boundaries. Site isolation is a core Chromium defense that separates web content into distinct processes to prevent cross-origin data theft. Bypassing this boundary undermines browser sandboxing guarantees on Android devices. Google rated the Chromium security severity as Medium.
Critical Impact
An attacker who compromises the renderer process can defeat site isolation via a crafted HTML page, enabling cross-origin integrity violations on Android Chrome installations before 150.0.7871.47.
Affected Products
- Google Chrome on Android prior to version 150.0.7871.47
- Chromium-based browsers on Android that share the vulnerable Input component
- Mobile applications embedding affected Chromium builds
Discovery Timeline
- 2026-06-30 - CVE-2026-13866 published to NVD
- 2026-07-01 - Last updated in NVD database
Technical Details for CVE-2026-13866
Vulnerability Analysis
The vulnerability resides in the Input handling code of Chrome on Android. Site isolation places cross-origin documents into separate renderer processes, ensuring that a compromised renderer cannot access data from other sites. The Input component's inappropriate implementation breaks this guarantee. An attacker who has already achieved code execution inside a renderer process can deliver a crafted HTML page that manipulates input handling to reach content or state belonging to a different origin. The issue is classified as [CWE-20: Improper Input Validation], indicating that untrusted input reaches security-sensitive code paths without adequate constraints. Exploitation requires user interaction, such as visiting an attacker-controlled page, and network access to deliver the crafted content.
Root Cause
The root cause is improper validation of input-related data or events within the renderer process on Android. Chromium relies on strict browser-process arbitration to enforce origin boundaries. When the Input component fails to validate assumptions about the originating frame or process, an already-compromised renderer can influence input flow in ways that cross the site isolation boundary. This defeats the process-per-site security model that Chrome uses to contain renderer compromises.
Attack Vector
Exploitation is a two-stage process. First, an attacker must compromise a Chrome renderer process, typically by chaining a separate memory corruption or logic bug. Second, the attacker delivers a crafted HTML page that exercises the vulnerable Input handling path to bypass site isolation. The bypass yields high impact to integrity because attacker-controlled content can influence data belonging to another origin. Confidentiality and availability impacts are not observed. No public exploit is available and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.
No verified proof-of-concept code is publicly available. See the Chromium Issue Tracker Entry for technical details when the report is unrestricted.
Detection Methods for CVE-2026-13866
Indicators of Compromise
- Android Chrome installations running versions below 150.0.7871.47 on managed endpoints
- Unexpected navigation events or cross-origin state changes originating from a single renderer process
- Browser crash reports referencing the Input component or site isolation enforcement code paths
Detection Strategies
- Inventory Chrome on Android across mobile fleets and flag builds below 150.0.7871.47 for prioritized remediation
- Correlate web proxy logs with endpoint browser telemetry to identify visits to unknown HTML content followed by anomalous cross-site requests
- Monitor mobile threat defense tooling for signals indicating renderer exploitation precursors, such as memory corruption crashes in Chrome
Monitoring Recommendations
- Enable Chrome enterprise reporting to surface version drift and crash telemetry from Android endpoints
- Track outbound requests from mobile devices to newly registered or low-reputation domains hosting HTML payloads
- Alert on Chrome for Android processes generating unexpected renderer restarts or sandbox violations
How to Mitigate CVE-2026-13866
Immediate Actions Required
- Update Google Chrome on Android to version 150.0.7871.47 or later through the Google Play Store
- Enforce mobile device management (MDM) policies that require the current Chrome version before granting access to sensitive resources
- Educate users to avoid opening untrusted links on Android devices until patching is confirmed
Patch Information
Google addressed CVE-2026-13866 in Chrome for Android 150.0.7871.47. Refer to the Google Chrome Desktop Update release notes and the Chromium Issue Tracker Entry for the corresponding fix. Deploy the update through Google Play or MDM-managed distribution channels.
Workarounds
- No vendor-supplied workaround exists; upgrading to the fixed Chrome version is the only supported remediation
- Restrict browsing on Android devices to trusted sites through URL filtering until the patch is applied
- Disable or limit use of Chrome on Android in high-risk roles until fleet-wide patch compliance is verified
# Verify installed Chrome version on an Android device via adb
adb shell dumpsys package com.android.chrome | grep versionName
# Expected output should be 150.0.7871.47 or later
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
