CVE-2026-11278 in Chrome
Summary
by MITRE • 06/05/2026
Inappropriate implementation in CustomTabs in Google Chrome on Android prior to 149.0.7827.53 allowed a local attacker to leak cross-origin data via a crafted HTML page. (Chromium security severity: Low)
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Analysis
by VulDB Data Team • 06/05/2026
The vulnerability resides in the CustomTabs implementation within Google Chrome on Android systems before version 149.0.7827.53, representing a significant security gap that enables local attackers to exploit cross-origin data leakage mechanisms. This issue falls under the category of improper access control and data exposure vulnerabilities, with the Chromium security severity classified as low but potentially impactful in specific contexts. The flaw manifests through a crafted HTML page that manipulates the CustomTabs functionality to access and exfiltrate sensitive data from different origins, exploiting the trust model between the browser and its components. The vulnerability stems from insufficient validation of cross-origin requests within the CustomTabs API, which should have enforced strict origin policies and access controls to prevent unauthorized data access.
The technical implementation flaw occurs at the interface level where CustomTabs handles external requests and manages the communication between the host application and external web content. When a malicious HTML page is loaded, it can leverage the CustomTabs functionality to make requests that bypass normal cross-origin restrictions, allowing the attacker to access resources that should be restricted to the originating domain. This exploitation pathway demonstrates a failure in the browser's security model where the boundary between different origins is not properly enforced during CustomTabs operations. The vulnerability specifically affects the way Chrome processes and validates cross-origin requests within its CustomTabs framework, creating an attack surface that allows local code execution and data exfiltration.
The operational impact of this vulnerability extends beyond simple data leakage, as it provides attackers with the capability to gather sensitive information from multiple origins within the same browsing context. A local attacker could craft malicious web pages that, when opened through CustomTabs, would enable them to access cookies, local storage, session data, and potentially other cross-origin resources that should remain isolated. This type of vulnerability aligns with CWE-284 access control flaws and represents a violation of the principle of least privilege in web security implementations. The attack vector operates through the local attack surface, meaning that no network access is required for exploitation, making it particularly concerning for mobile environments where local code execution can occur through various attack vectors including malicious applications or compromised user interactions.
Mitigation strategies should focus on implementing proper origin validation and access control mechanisms within the CustomTabs implementation, ensuring that all cross-origin requests are properly authenticated and authorized before processing. The recommended approach includes strengthening the validation of origin parameters within the CustomTabs API, implementing stricter sandboxing controls, and ensuring that the browser enforces proper isolation between different origins during CustomTabs operations. Security updates should include enhanced input validation, proper access control enforcement, and comprehensive testing of cross-origin scenarios to prevent similar vulnerabilities from arising in future implementations. Organizations should also consider implementing network monitoring to detect unusual CustomTabs activity and ensure that users are running updated versions of Chrome that contain the necessary security patches. The fix should align with established security practices from the ATT&CK framework, particularly those related to privilege escalation and credential access, ensuring that the vulnerability does not provide a pathway for more serious security breaches.