CVE-2026-79256 in Chrome
Summary
by MITRE • 08/26/2026
Externally controlled reference in WebView in Google Chrome on on Android prior to 152.0.7977.65 allowed a remote attacker who had compromised the renderer process to potentially execute arbitrary code outside the sandbox via a crafted HTML page. (Chromium security severity: Medium)
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Analysis
by VulDB Data Team • 08/26/2026
The vulnerability identified in Google Chrome for Android prior to version 152.0.7977.65 represents a critical failure in boundary enforcement between the browser's rendering engine and its native application components. Specifically, this flaw involves an externally controlled reference within the WebView implementation, which serves as a bridge allowing web content to interact with underlying system APIs. In a properly secured architecture, such interactions must be strictly validated against a whitelist of allowed actions or parameters to prevent malicious actors from leveraging these interfaces for unauthorized operations. The presence of an unvalidated external reference indicates that the application failed to adequately sanitize inputs derived from remote sources before passing them to sensitive internal functions. This type of architectural weakness is commonly categorized under CWE-470, which describes use of externally-controlled references in unsafe contexts, highlighting a fundamental lapse in input validation protocols within the WebView subsystem.
The operational impact of this vulnerability is severe due to its potential for sandbox escape. Typically, web content executes within an isolated environment known as the renderer process sandbox, designed to restrict access to system resources and prevent arbitrary code execution on the host device. However, when a remote attacker compromises the renderer process through other means or exploits a separate initial entry point, they can leverage this WebView flaw to break out of that isolation boundary. By crafting a specific HTML page containing malicious scripts, an attacker could manipulate the external reference to invoke native methods with elevated privileges. This allows for the execution of arbitrary code outside the sandbox, effectively granting the attacker control over the Android operating system layer rather than just the browser context. Such capabilities align closely with MITRE ATT&CK technique T1059, specifically command and script interpretation within mobile environments, as well as potential privilege escalation vectors where lateral movement from a low-privilege web process to high-privilege native processes occurs.
From a technical perspective, this issue underscores the complexity of maintaining security in hybrid application architectures that combine web technologies with native code execution capabilities. The WebView component acts as a crucial interface for displaying rich media and complex layouts but also expands the attack surface significantly if not configured securely. In this instance, the lack of rigorous checks on references passed from JavaScript to Java or Kotlin layers created an exploitable pathway. Attackers could construct payloads that trigger unintended side effects by supplying crafted arguments that bypass expected constraints. The Chromium security team classified this as a medium severity issue primarily because it requires prior compromise of the renderer process, which acts as a secondary barrier. Nevertheless, given the prevalence of cross-site scripting and other web-based exploits that can achieve initial renderer access, the risk remains substantial for end-users who visit maliciously crafted websites or interact with compromised ad networks.
Mitigation strategies must focus on both immediate patching and long-term architectural improvements. The primary remediation is to update Google Chrome for Android to version 152.0.7977.65 or later, where the validation logic for WebView references has been strengthened. Developers integrating WebView into custom applications should ensure they are using updated libraries that incorporate these fixes. Furthermore, implementing strict Content Security Policy directives can help mitigate initial entry points by restricting script execution sources and preventing inline scripts from running without explicit approval. Enabling additional security features such as sandboxing flags in the WebView configuration can further limit the scope of potential damage if an exploit is attempted. Regular audits of code that handles external inputs are essential to prevent similar vulnerabilities, ensuring that all data flowing between web layers and native components undergoes rigorous type checking and value validation before execution.