CVE-2026-87584 in Chrome
Summary
by MITRE • 09/09/2026
Incorrect authorization in WebUI 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: Medium)
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability identified as an incorrect authorization flaw within the WebUI component of Google Chrome prior to version 153.0.8010.36 represents a critical failure in access control mechanisms designed to protect privileged interfaces from unauthorized user interaction. This security severity, classified as Medium by the Chromium team, stems from a logic error where the browser fails to properly validate whether the entity initiating an action possesses the necessary privileges to execute it on sensitive system pages. In modern web browsers, WebUI serves as the interface for internal settings and diagnostic tools that are typically restricted to prevent malicious websites or scripts from altering core configurations or accessing private data. When this authorization check is bypassed via a crafted HTML page, an attacker can effectively elevate their access level within the browser environment without requiring user consent or authentication credentials beyond what is already present in the session.
From a technical perspective, this flaw allows for unauthorized manipulation of privileged pages through standard web delivery mechanisms such as phishing links or compromised websites hosting malicious scripts. The attack vector relies on social engineering combined with code execution capabilities inherent to HTML and JavaScript environments. By crafting specific requests that exploit the missing authorization checks, an attacker can trigger actions intended only for administrators or system-level processes. This bypass undermines the principle of least privilege, which dictates that users should have access only to those resources necessary for their role. The existence of such a flaw indicates a gap in the input validation and permission verification logic within the WebUI framework, allowing external inputs to influence internal state changes that were previously protected by strict access controls.
The operational impact of this vulnerability is significant as it compromises the integrity and confidentiality of browser settings and potentially user data stored locally or synced with accounts. An attacker who successfully exploits this flaw could modify security-related configurations, disable protective features such as safe browsing indicators, or redirect traffic to malicious domains without detection by standard security warnings. This level of access facilitates further attacks including credential theft via phishing pages that appear legitimate due to altered settings, installation of unwanted extensions, or exfiltration of sensitive information cached within the browser profile. The ability to bypass system access restrictions effectively turns a standard browsing session into a compromised environment where the user loses control over their digital identity and security posture.
Mitigation strategies primarily involve immediate software updates to ensure that all instances of Google Chrome are upgraded to version 153.0.8010.36 or later, which contains patches for this authorization logic error. Organizations should enforce automated update policies to minimize the window of exposure across their endpoints. Additionally, users can employ browser hardening techniques such as disabling JavaScript on untrusted sites using extensions like NoScript, although this may impact usability. Implementing strict Content Security Policies and monitoring for unusual changes in browser configuration settings can also help detect potential exploitation attempts. Regular security audits focusing on access control implementations within web applications are essential to prevent similar authorization bypasses in future software releases.
This vulnerability aligns with CWE-285, which describes Improper Authorization, where the application does not perform sufficient checks before granting a user permission to an action or resource. It also maps to MITRE ATT&CK technique T1078, Valid Accounts, as it allows an attacker to leverage existing session tokens to access restricted areas without valid credentials for those specific privileged functions. Understanding these mappings helps in categorizing the risk within broader threat intelligence frameworks and ensures that defensive measures are aligned with industry-standard classifications of security weaknesses. Addressing this issue requires a holistic approach combining timely patch management, user awareness training regarding suspicious web content, and robust technical controls to validate permissions at every layer of the application stack.