CVE-2026-11278 Overview
CVE-2026-11278 is an inappropriate implementation vulnerability in the CustomTabs component of Google Chrome on Android. The flaw affects versions prior to 149.0.7827.53 and allows a local attacker to leak cross-origin data through a crafted HTML page. The issue is categorized under [CWE-346] Origin Validation Error, indicating a failure to properly enforce origin boundaries within CustomTabs. Google classifies the Chromium security severity as Low, while the NVD assigns a CVSS 3.1 base score of 6.5. Exploitation requires user interaction, but the attack vector is network-based through a malicious web page rendered in CustomTabs.
Critical Impact
A crafted HTML page can leak cross-origin data from other web origins, breaking the same-origin policy that protects user sessions and sensitive content in Chrome on Android.
Affected Products
- Google Chrome on Android prior to 149.0.7827.53
- Google Android platform hosting vulnerable Chrome versions
- Applications embedding Chrome CustomTabs from affected builds
Discovery Timeline
- 2026-06-05 - CVE-2026-11278 published to NVD
- 2026-06-10 - Last updated in NVD database
Technical Details for CVE-2026-11278
Vulnerability Analysis
The vulnerability resides in Chrome's CustomTabs implementation on Android. CustomTabs allow native Android applications to embed a Chrome-rendered browser surface while preserving cookies, autofill, and saved passwords from the user's Chrome profile. The inappropriate implementation breaks isolation between origins loaded inside this surface. An attacker who controls an HTML page rendered in CustomTabs can read data that belongs to a different origin, violating the same-origin policy enforced by the browser.
The condition is reachable from any web page that the user is convinced to open in CustomTabs. Once loaded, the crafted page executes logic that observes cross-origin responses or DOM state that should remain partitioned. The result is disclosure of confidential content, though integrity and availability remain intact.
Root Cause
The root cause is an origin validation failure ([CWE-346]) inside the CustomTabs surface. Chrome fails to apply the same origin boundary enforcement that protects standard browser tabs. The defect is local to the Android platform code path and does not affect Chrome on desktop operating systems. Google fixed the issue in Chrome 149.0.7827.53 for the stable channel.
Attack Vector
Exploitation requires the victim to open a crafted link inside a CustomTabs view, typically launched from a third-party Android application. The attacker hosts a malicious HTML page that, when rendered in the vulnerable CustomTabs surface, harvests cross-origin data accessible to the user's Chrome profile. No elevated privileges are required, and no malware needs to be installed on the device. The exploitation flow is described in the Chromium Issue Tracker Entry and the Google Chrome Update Announcement.
Detection Methods for CVE-2026-11278
Indicators of Compromise
- Android devices running Chrome versions earlier than 149.0.7827.53 while users browse via CustomTabs sessions.
- Outbound requests from mobile clients to unfamiliar domains immediately after a CustomTabs handoff from another app.
- Unexpected exfiltration patterns where cross-origin response bodies appear in attacker-controlled telemetry endpoints.
Detection Strategies
- Inventory Chrome for Android installations across managed devices and flag any version below 149.0.7827.53.
- Inspect Mobile Device Management (MDM) reports for Chrome update compliance and correlate with browsing telemetry where available.
- Hunt for suspicious deep links and intent handlers in third-party apps that force navigation into CustomTabs targeting unknown domains.
Monitoring Recommendations
- Monitor web proxy and DNS logs from mobile networks for connections to newly registered domains served through CustomTabs flows.
- Track Android application installations that abuse ACTION_VIEW intents to redirect users into CustomTabs without user awareness.
- Alert on Chrome version drift in fleet-wide reporting until all endpoints reach the patched build.
How to Mitigate CVE-2026-11278
Immediate Actions Required
- Update Google Chrome on Android to version 149.0.7827.53 or later through the Google Play Store.
- Enforce minimum browser version policies through MDM for corporate-owned and BYOD Android devices.
- Educate users to avoid opening untrusted links from messaging apps or untrusted Android applications until patching is verified.
Patch Information
Google released the fix in Chrome 149.0.7827.53 on the stable channel for Android. Details are published in the Google Chrome Update Announcement, with technical references tracked in the Chromium Issue Tracker Entry. Devices configured for automatic updates through Google Play will receive the patched build without administrator action.
Workarounds
- Disable or restrict third-party apps that launch CustomTabs to untrusted destinations until Chrome is updated.
- Use an alternative browser app or full Chrome tabs instead of CustomTabs sessions for sensitive workflows during the patch window.
- Apply Android Enterprise managed configurations to force Chrome auto-updates and prevent downgrade to vulnerable versions.
# Verify installed Chrome version on a managed Android device via adb
adb shell dumpsys package com.android.chrome | grep versionName
# Expected output after remediation: versionName=149.0.7827.53 or later
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
