CVE-2026-13863 Overview
CVE-2026-13863 is a privilege escalation vulnerability in Google Chrome for Android. The flaw resides in the CustomTabs component and stems from insufficient validation of untrusted input [CWE-20]. A local attacker can exploit this issue by delivering a malicious file to a targeted device. Successful exploitation elevates privileges within the mobile environment. The vulnerability affects Google Chrome on Android versions prior to 150.0.7871.47. Chromium security assigned this issue a Medium severity rating, while NVD scored it 7.8 (High) reflecting the impact on confidentiality, integrity, and availability once local access and user interaction are achieved.
Critical Impact
A local attacker can escalate privileges on an Android device running vulnerable Chrome builds by tricking a user into interacting with a malicious file through CustomTabs.
Affected Products
- Google Chrome on Android prior to 150.0.7871.47
- Chromium-based Android browsers embedding the vulnerable CustomTabs component
- Android applications that invoke Chrome CustomTabs for in-app browsing
Discovery Timeline
- 2026-06-30 - CVE-2026-13863 published to NVD
- 2026-07-02 - Last updated in NVD database
Technical Details for CVE-2026-13863
Vulnerability Analysis
The vulnerability sits in Chrome's CustomTabs implementation on Android. CustomTabs allow third-party Android applications to launch Chrome-rendered browser tabs while sharing state such as cookies, saved passwords, and autofill data. This tight integration means CustomTabs frequently handle file-based inputs supplied by the calling application or fetched from the web. Chrome fails to sufficiently validate certain untrusted inputs routed through this surface. A malicious file processed through the CustomTabs code path can drive Chrome into operations that a local attacker would not otherwise be authorized to perform. The result is privilege escalation on the affected Android device.
Root Cause
The root cause is improper input validation classified under [CWE-20]. The CustomTabs code path accepts input attributes tied to file handling without enforcing sufficient constraints. When a crafted file reaches this path, Chrome performs privileged actions on behalf of the caller. Because CustomTabs run within Chrome's process context, the elevated actions execute with Chrome's permissions rather than the caller's, producing the privilege escalation.
Attack Vector
Exploitation requires local access and user interaction. An attacker plants or delivers a malicious file, typically bundled inside a companion application or shared via messaging or storage. When the victim opens the file through a workflow that invokes Chrome CustomTabs, the crafted input traverses the vulnerable code path. Chrome then executes with the attacker's controlled parameters, allowing the attacker to gain higher privileges than the originating app should possess. No network attack vector or authenticated remote session is required.
No public proof-of-concept code is available. Technical details are limited to the Chromium Issue Tracker Entry and the Google Chrome Stable Channel Update.
Detection Methods for CVE-2026-13863
Indicators of Compromise
- Installed Chrome for Android versions earlier than 150.0.7871.47 on managed devices
- Third-party Android applications invoking Chrome CustomTabs with unexpected file URIs or intents
- Unusual file-open activity followed by Chrome executing privileged operations on the device
Detection Strategies
- Inventory mobile endpoints and flag Chrome for Android builds below 150.0.7871.47 through mobile device management (MDM) posture checks.
- Monitor Android application logs for CustomTabs intents carrying suspicious file:// or content:// URIs originating from untrusted apps.
- Correlate installation of unknown APKs with subsequent Chrome CustomTabs launches to identify staging behavior.
Monitoring Recommendations
- Enable telemetry collection from managed Android devices, including Chrome version reporting and intent audit logs.
- Alert on sideloaded applications that register handlers for common document MIME types and immediately invoke CustomTabs.
- Review mobile threat defense reports for privilege escalation attempts tied to browser components.
How to Mitigate CVE-2026-13863
Immediate Actions Required
- Update Google Chrome on Android to version 150.0.7871.47 or later through Google Play.
- Enforce automatic Chrome updates on managed devices via MDM policy.
- Restrict installation of unknown or sideloaded APKs on corporate-owned Android endpoints.
- Audit installed applications that make heavy use of Chrome CustomTabs and validate their publishers.
Patch Information
Google addressed CVE-2026-13863 in Chrome for Android version 150.0.7871.47. Refer to the Google Chrome Stable Channel Update for release notes and to the Chromium Issue Tracker Entry for issue tracking details. Chromium-based Android browsers that embed the affected component should adopt the corresponding upstream fix.
Workarounds
- Instruct users to avoid opening untrusted files that trigger in-app browser tabs until Chrome is patched.
- Disable installation from unknown sources through Android device policy to block malicious file delivery via sideloaded apps.
- Where feasible, prefer applications that use WebView under strict sandboxing over those relying on Chrome CustomTabs for third-party file handling.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
