CVE-2026-87443 in Chrome
Summary
by MITRE • 09/09/2026
Missing authorization in Actor in Google Chrome prior to 153.0.8010.36 allowed a remote attacker to obtain sensitive information via a crafted HTML page. (Chromium security severity: Medium)
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability identified as missing authorization within the actor component of Google Chrome, specifically affecting versions prior to 153.0.8010.36, represents a critical flaw in access control mechanisms that governs how different entities interact with browser resources. This issue stems from an insufficient check on permissions when handling requests initiated by specific actors or components within the Chromium engine architecture. In modern web browsers, various internal processes and extensions operate under distinct privilege levels to isolate sensitive operations such as file system access, network communication, and user data retrieval. When these isolation boundaries are compromised due to missing authorization checks, it allows for unauthorized escalation of privileges where a lower-privileged entity can perform actions reserved for higher-privileged contexts or bypass intended restrictions entirely.
From a technical perspective, this flaw likely involves the failure to validate whether an incoming request from a web page or script possesses the necessary credentials or permissions to access specific internal APIs or data structures. The term actor in Chromium often refers to entities that execute code within isolated worlds, such as content scripts or extension backgrounds. If the browser fails to enforce strict authorization protocols when these actors interact with privileged interfaces, an attacker can craft a malicious HTML page designed to exploit this gap. By leveraging JavaScript techniques and potentially abusing cross-origin resource sharing policies or internal API endpoints, the crafted payload can trick the browser into exposing sensitive information that should remain hidden from untrusted web content.
The operational impact of this vulnerability is significant as it enables remote attackers to obtain sensitive user information without any physical access or prior authentication on the target system. An attacker could host a malicious website containing specially constructed HTML and JavaScript code that, when visited by an unsuspecting user running an affected version of Chrome, triggers the unauthorized data exfiltration. This could lead to the disclosure of personal identifiable information, session tokens, cookies, or other confidential data stored within the browser context. Such breaches undermine the fundamental trust model of web browsing, where users expect their private data to remain secure even when visiting potentially untrusted sites. The severity is classified as medium because while it allows for sensitive data leakage, it typically requires user interaction such as navigating to a specific URL and may not provide full system compromise but rather targeted information theft.
This vulnerability aligns with CWE-284 Improper Access Control, which describes situations where an actor can access resources or functionality that they are not authorized to use. Furthermore, in the context of the MITRE ATT&CK framework, this behavior corresponds to techniques related to Collection and Exfiltration over C2 channels if the stolen data is sent back to a remote server, specifically falling under categories like Browser Data Stolen from Local Storage or similar mechanisms depending on the exact vector used for extraction. The lack of proper authorization checks creates an opportunity for information disclosure that can be chained with other vulnerabilities to achieve more severe outcomes such as account takeover or identity theft.
To mitigate this risk, users and organizations must ensure that Google Chrome is updated to version 153.0.8010.36 or later immediately upon availability. This update contains the necessary patches to enforce stricter authorization checks within the actor component, thereby closing the gap that allowed unauthorized data access. Additionally, implementing browser hardening policies can help reduce exposure by disabling unnecessary features or restricting permissions for extensions and scripts where possible. Security awareness training is also recommended to educate users about the risks of visiting untrusted websites, as social engineering often accompanies such exploits to lure victims into triggering the malicious payload. Regular monitoring of security advisories from Google and prompt application of patches are essential practices in maintaining a secure browsing environment against evolving web-based threats.