CVE-2026-87476 in Chrome
Summary
by MITRE • 09/09/2026
Incorrect authorization in Loader 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 an incorrect authorization flaw within the loader component of Google Chrome, specifically affecting versions prior to 153.0.8010.36, represents a significant breach in the browser's access control mechanisms. This issue stems from a failure in the internal logic that governs how resources are loaded and accessed by web pages. In modern browsers like Chrome, the loader is responsible for fetching various types of content such as scripts, stylesheets, images, and other assets required to render a webpage securely. The core technical flaw lies in the improper validation of authorization checks during this loading process. When a malicious actor crafts an HTML page designed to exploit this weakness, they can bypass expected security boundaries that are meant to restrict access to sensitive data or internal browser states. This misconfiguration allows the attacker's script to interact with resources it should not have permission to access, effectively circumventing the same-origin policy and other isolation mechanisms intended to protect user privacy and system integrity.
From a technical perspective, this vulnerability falls under the category of improper privilege management where the application fails to enforce appropriate restrictions on authenticated users or processes. In the context of web browsers, this often relates to how cross-origin requests are handled or how internal APIs expose sensitive information to untrusted scripts. The attacker leverages a crafted HTML page that likely utilizes specific JavaScript techniques to trigger the loader in a way that exploits the authorization gap. By doing so, they can retrieve data that is typically shielded from web content, such as cookies, local storage contents, or potentially more critical internal browser variables depending on the exact implementation details of the flaw. The severity is rated as medium by Chromium security standards because while it allows for information disclosure, it generally does not provide direct code execution capabilities unless combined with other vulnerabilities to escalate privileges further.
The operational impact of this vulnerability centers around unauthorized data access and potential privacy violations. A successful exploitation could allow a remote attacker to steal sensitive user information stored within the browser environment. This might include session tokens that could lead to account takeover, personal identifiable information cached by web applications, or internal configuration details that aid in further attacks. The ability to obtain this sensitive information via a simple crafted HTML page means that an attack can be initiated through social engineering tactics such as phishing emails containing malicious links or visiting compromised websites. Once the user interacts with the payload, even passively depending on browser autoplay policies and script execution rules, the attacker gains visibility into data that should remain confidential. This undermines the trust users place in their web browsers to isolate untrusted content from sensitive local resources.
To mitigate this risk, it is imperative for all users running Google Chrome prior to version 153.0.8010.36 to update immediately to the latest stable release where these authorization checks have been corrected and hardened. The patch addresses the logic errors in the loader component ensuring that proper validation occurs before any resource access is granted. In addition to updating software, organizations should enforce strict content security policies within their web applications to minimize the attack surface available to potential exploiters. Monitoring for unusual network traffic patterns or script behaviors associated with known exploitation techniques can also provide an additional layer of defense. Security teams should remain vigilant as attackers often combine such information disclosure flaws with other vulnerabilities like cross-site scripting to achieve more severe outcomes, making timely patching and robust security hygiene essential components of a comprehensive defense strategy against browser-based threats aligned with CWE-269 for improper privilege management and ATT&CK techniques related to credential access or data exfiltration.