CVE-2026-87493 in Chrome
Summary
by MITRE • 09/09/2026
Missing authorization in FileSystem in Google Chrome prior to 153.0.8010.36 allowed a remote attacker leveraging social engineering to bypass system access restrictions 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 file system handling mechanisms of Google Chrome prior to version 153.0.8010.36 represents a significant breach in browser-based isolation boundaries. This flaw specifically affects how the Chromium engine processes requests for local file access, failing to adequately verify whether the executing context possesses the necessary permissions to interact with specific areas of the host operating system's file hierarchy. In modern web browsers, strict same-origin policies and sandboxing are designed to prevent malicious websites from accessing sensitive user data or modifying system files without explicit consent. However, in this instance, the authorization checks were insufficient, allowing a crafted HTML page to bypass these standard security restrictions when executed within an affected browser version.
The operational impact of this vulnerability is primarily driven by social engineering tactics rather than purely automated exploitation techniques. An attacker would need to lure a victim into visiting a specially constructed web page that contains malicious code designed to trigger the file system access flaw. Once the user interacts with or loads this crafted content, the browser may inadvertently grant the webpage elevated privileges to read, write, or delete files on the local machine. This capability undermines the fundamental trust model of the web platform, where users expect their personal data and system integrity to remain protected from arbitrary remote code execution contexts. The severity is classified as medium because while it allows for unauthorized access, it typically requires user interaction such as clicking a link or loading a specific page, which limits its scope compared to fully automated drive-by exploits that require no user action.
From a technical classification perspective, this vulnerability aligns with CWE-269, Improper Privilege Management, specifically regarding the failure to enforce proper authorization checks before granting access to system resources. It also relates closely to CWE-732, Incorrect Permission Assignment for Critical Resource, as the browser fails to correctly assign or verify permissions for file operations initiated by web content. In terms of offensive security frameworks, this behavior maps to MITRE ATT&CK technique T1059, Command and Scripting Interpreter, if used in conjunction with further exploitation steps, but more directly it reflects aspects of privilege escalation within the application layer where a lower-privileged context gains access to higher-privileged resources. The lack of strict authorization checks allows an untrusted origin to perform actions that should be restricted to trusted contexts or require explicit user permission dialogs that were either bypassed or not properly triggered due to the flaw in logic.
Mitigation for this vulnerability requires immediate action by updating Google Chrome to version 153.0.8010.36 or later, where these authorization checks have been corrected and strengthened. Users should ensure automatic updates are enabled to receive security patches promptly as they become available. For organizations managing multiple endpoints, deploying centralized browser update policies can help mitigate the risk of exposure across a network. Additionally, users should remain vigilant against social engineering attempts, avoiding interaction with untrusted web content that requests unusual permissions or appears designed to manipulate file system interactions. Security administrators may also consider implementing application control solutions or strict Content Security Policies in enterprise environments to further restrict what types of scripts and resources can execute within the browser environment, adding an additional layer of defense beyond the browser's native security features.