CVE-2026-87544 in Chrome
Summary
by MITRE • 09/09/2026
Incorrect authorization in Extensions in Google Chrome prior to 153.0.8010.36 allowed a remote attacker to bypass system access restrictions into a privileged page via a crafted HTML page. (Chromium security severity: Low)
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability identified as an incorrect authorization issue within the Extensions subsystem of Google Chrome prior to version 153.0.8010.36 represents a critical failure in access control mechanisms that governs how browser extensions interact with privileged internal pages. This flaw allows a remote attacker, who can trick a user into visiting a specifically crafted HTML page or interacting with a malicious extension, to bypass system-level access restrictions. The core technical deficiency lies in the insufficient validation of permissions when an extension attempts to access resources designated for higher privilege levels within the browser architecture. By exploiting this misconfiguration, an adversary can execute code or retrieve sensitive data from privileged pages that are normally isolated from standard web content and lower-privilege extensions, effectively elevating their scope of influence beyond what is intended by the security model.
From a technical perspective, this vulnerability aligns with CWE-269, which describes Improper Privilege Management, specifically where an actor obtains privileges it should not have due to flawed authorization logic. The attack vector typically involves social engineering or drive-by download techniques where the victim is induced to install a malicious extension or visit a webpage that leverages existing installed extensions to perform unauthorized actions. Once inside the privileged context, the attacker may be able to access cookies, local storage, or internal browser APIs that are restricted from normal web pages. This bypass of security boundaries undermines the principle of least privilege and compromises the integrity of the browsing session, potentially leading to data exfiltration, session hijacking, or further lateral movement within the user's environment if combined with other vulnerabilities.
The operational impact of this vulnerability is significant for users who rely on browser extensions for productivity, security, or personalization tasks. An attacker successfully exploiting this flaw can gain unauthorized access to sensitive information stored in privileged contexts, such as authentication tokens or private configuration data. This could result in account compromise, identity theft, or the ability to manipulate user interactions without consent. Although classified with a low severity rating by Chromium's internal metrics, likely due to the complexity required for exploitation or limited direct impact on system stability, the potential for unauthorized access remains high because it targets the fundamental trust model between extensions and the browser core. The risk is amplified in enterprise environments where extensions are often deployed centrally, as a single compromised extension could expose data across multiple user accounts if proper sandboxing fails to contain the breach.
To mitigate this vulnerability, organizations and individual users must ensure that Google Chrome is updated to version 153.0.8010.36 or later immediately upon availability. This update contains patches for the authorization checks within the Extensions subsystem, ensuring that access requests are properly validated against defined permission scopes before granting entry to privileged pages. Additionally, administrators should enforce strict policies regarding which extensions can be installed and what permissions they are granted, adhering to industry best practices outlined in frameworks like MITRE ATT&CK technique T1059, Command and Scripting Interpreter, where malicious scripts or code execution is a common outcome of such privilege escalation flaws. Regular auditing of extension permissions and disabling unused extensions further reduces the attack surface by limiting the number of potential entry points for this type of authorization bypass.