CVE-2026-87498 in Chrome
Summary
by MITRE • 09/09/2026
Missing authorization in WebUI in Google Chrome prior to 153.0.8010.36 allowed a remote attacker who had compromised the renderer process to bypass web origin policy via a crafted HTML page. (Chromium security severity: High)
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability identified as missing authorization within the WebUI of Google Chrome prior to version 153.0.8010.36 represents a critical failure in access control mechanisms that governs interactions between web content and browser internals. This flaw specifically impacts the privilege separation model inherent to modern browsers, where renderer processes are expected to operate with restricted permissions compared to the main browser process or privileged WebUI components. When an attacker successfully compromises a renderer process through other means, such as exploiting a separate vulnerability in JavaScript execution or DOM manipulation, they gain a foothold within this sandboxed environment. The absence of proper authorization checks allows this compromised renderer to issue requests to internal Chrome interfaces that should be inaccessible from untrusted contexts, effectively breaking the isolation boundaries designed to protect user data and system integrity.
From a technical perspective, the core issue lies in the insufficient validation of origin policies when handling API calls or resource accesses initiated by WebUI components. In standard Chromium architecture, web origins are strictly enforced to prevent cross-origin attacks and unauthorized access to sensitive browser features. However, due to this specific authorization gap, a crafted HTML page hosted on an attacker-controlled domain can exploit the lack of verification to interact with privileged endpoints. This interaction enables the remote attacker to bypass web origin policies, which serve as the primary defense against data leakage and state manipulation across different websites. The severity is classified as high because it facilitates privilege escalation from a low-privilege renderer context to higher-level browser functionalities without requiring additional user interaction or complex exploitation chains beyond initial code execution in the sandboxed environment.
The operational impact of this vulnerability is significant, particularly for users who visit maliciously crafted web pages while using affected versions of Chrome. An attacker can leverage this flaw to exfiltrate sensitive information stored within the browser context, such as cookies, local storage data, or session tokens belonging to other trusted sites. Furthermore, it may allow for unauthorized actions on behalf of the user, including modifying settings, accessing private tabs, or interacting with internal management interfaces that are not intended for public web access. This undermines the fundamental trust model of the browser and exposes users to sophisticated phishing campaigns, account takeover attempts, and persistent surveillance if combined with other exploitation techniques. The ability to bypass origin policies effectively neutralizes one of the most important security features in modern web browsing, leaving systems vulnerable to a wide array of downstream attacks that rely on accessing restricted resources.
To mitigate this risk, it is imperative for users to update Google Chrome immediately to version 153.0.8010.36 or later, where these authorization checks have been reinforced and the origin policy enforcement has been corrected. Organizations should ensure that endpoint protection strategies include automated patch management systems capable of deploying browser updates across all endpoints promptly. Additionally, security teams can employ content security policies (CSP) to restrict inline scripts and external resource loading on internal corporate web applications, reducing the attack surface available for initial renderer compromise. Monitoring network traffic for unusual requests directed at local Chrome interfaces or localhost addresses may also help detect exploitation attempts in real-time. Regular audits of browser configurations and adherence to industry standards such as CWE-269 (Improper Privilege Management) and ATT&CK techniques related to privilege escalation via sandbox escape are recommended practices to maintain robust security postures against similar vulnerabilities.