CVE-2026-103626 in Chrome
Summary
by MITRE • 10/02/2026
Incorrect authorization in FileSystem in Google Chrome on on Windows prior to 154.0.8037.97 allowed a remote attacker leveraging social engineering to potentially execute arbitrary code outside the sandbox via a crafted HTML page. (Chromium security severity: High)
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Analysis
by VulDB Data Team • 10/02/2026
The vulnerability identified as an incorrect authorization flaw within the FileSystem component of Google Chrome on Windows represents a significant breach in browser isolation mechanisms. This issue stems from improper access control checks that allow processes or scripts operating outside the strict sandbox environment to interact with file system resources in ways intended only for privileged contexts. In modern web browsers, particularly Chromium-based engines like Chrome, critical components run within sandboxes to limit the potential damage of a successful exploit. By restricting these components to read-only access or specific allowed operations, the browser ensures that even if an attacker gains code execution capabilities through other vectors such as JavaScript injection, they cannot easily modify system files or escalate privileges. However, this particular flaw in the FileSystem API bypasses those restrictions under certain conditions on Windows systems prior to version 154.0.8037.97.
The technical nature of this vulnerability involves a failure in validating user permissions when handling file system operations initiated via web pages. When a remote attacker crafts an HTML page containing malicious JavaScript, they can attempt to perform write or delete operations on files located outside the designated sandboxed directories. Due to the authorization error, the browser fails to correctly deny these requests if the target path is not explicitly protected by standard sandbox boundaries. This allows the script to manipulate files in locations that are typically restricted for untrusted web content, such as user profile directories or application data folders. The exploitation relies heavily on social engineering tactics because it requires the victim to visit a malicious website and potentially grant permissions through browser dialogs or exploit default settings that allow certain file interactions without explicit consent.
From an operational impact perspective, this vulnerability enables arbitrary code execution outside the sandbox, which is considered one of the most severe outcomes in web security. Once an attacker can write executable files or modify configuration scripts in accessible directories, they can establish persistence on the victim's machine or execute further payloads with higher privileges than those granted to the browser process itself. This effectively neutralizes the primary defense mechanism provided by sandboxing, allowing lateral movement within the local system and potentially leading to full compromise of the user account. The severity is rated as High because it bridges the gap between remote code execution in a restricted context and unrestricted access on the host operating system, significantly increasing the risk profile for organizations relying on Chrome for secure browsing activities.
This flaw aligns with Common Weakness Enumeration (CWE) category CWE-269, which describes Improper Privilege Management, specifically where an actor obtains privileges they are not entitled to. It also relates closely to CWE-732, concerning Incorrect Permission Assignment for Critical Resource, as the file system permissions were not correctly applied or checked during runtime operations within the browser context. In terms of MITRE ATT&CK framework mapping, this vulnerability facilitates techniques associated with Initial Access through Spearphishing Link and subsequent Execution via Scripting Interpreter, allowing attackers to leverage trusted applications like Chrome to deploy malware on target systems without triggering traditional endpoint detection alerts that look for external binary downloads.
Mitigation strategies primarily involve updating Google Chrome to version 154.0.8037.97 or later, where the authorization checks in the FileSystem component have been corrected to enforce strict sandbox boundaries regardless of the initiating context. Organizations should ensure automatic updates are enabled across all endpoints to minimize exposure windows. Additionally, security administrators can implement application control policies that restrict JavaScript execution from untrusted sources and monitor for unusual file system write operations originating from browser processes. User awareness training remains critical as social engineering is a prerequisite vector; educating users about the risks of visiting unknown websites helps reduce the likelihood of successful exploitation even if technical controls are temporarily bypassed or delayed in deployment cycles.