CVE-2026-106198 in Chrome
Summary
by MITRE • 10/06/2026
Missing authorization in FileSystem in Google Chrome prior to 155.0.8059.39 allowed a remote attacker who had compromised the renderer process to bypass web origin policy via a crafted HTML page. (Chromium security severity: Medium)
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Analysis
by VulDB Data Team • 10/06/2026
The vulnerability identified as missing authorization within the FileSystem API of Google Chrome prior to version 155.0.8059.39 represents a significant breach in browser isolation mechanisms, specifically targeting the web origin policy. This flaw allows an attacker who has already achieved code execution within a renderer process to escalate privileges and access resources that should be strictly isolated from their current context. The core technical issue lies in the insufficient validation of authorization tokens or permissions when interacting with file system operations through JavaScript APIs. In modern browsers, each tab or frame operates under a distinct origin policy designed to prevent malicious scripts on one site from accessing data belonging to another. However, this vulnerability indicates that certain FileSystem-related functions did not strictly enforce these boundaries, effectively allowing cross-origin access to local files or directory structures when invoked by compromised renderer processes.
From an operational perspective, the impact of this flaw is severe for users who rely on web applications to handle sensitive documents locally. An attacker leveraging a crafted HTML page could exploit this misconfiguration to read, modify, or delete files that are not part of their designated sandboxed environment. This capability undermines the fundamental security model of the browser, which relies heavily on process isolation and origin separation to contain potential exploits. By bypassing these controls, an adversary can potentially exfiltrate sensitive user data stored locally, such as configuration files, cached credentials, or personal documents, thereby transforming a contained renderer compromise into a broader system-level breach. The severity is classified as medium within the Chromium security framework because while it requires initial access to the renderer process, the resulting impact on confidentiality and integrity of local resources is substantial.
This vulnerability aligns with Common Weakness Enumeration (CWE) category CWE-269, which describes Improper Authorization, where a user or system attempts to perform an action without having the necessary permissions. Furthermore, in the context of the MITRE ATT&CK framework for enterprise security, this behavior corresponds to techniques involving Lateral Movement and Data Staging within browser-based attacks. Attackers often use compromised renderer processes as a foothold to pivot into more sensitive areas of the user environment or to stage data before exfiltration. The failure to enforce strict authorization checks during file system interactions creates an avenue for such pivoting, allowing malicious scripts to traverse directory structures beyond their intended scope.
Mitigation strategies primarily involve updating Google Chrome to version 155.0.8059.39 or later, where the underlying code has been patched to correctly validate permissions before executing FileSystem API calls. Security administrators should ensure that automatic updates are enabled for all endpoints running this browser to minimize exposure windows. Additionally, users can reduce risk by disabling JavaScript in untrusted sites via content settings and employing strict Content Security Policy (CSP) headers on web applications they interact with frequently. These measures help limit the attack surface available to potential renderer exploits and reinforce the isolation boundaries that the vulnerability sought to bypass. Continuous monitoring of browser security advisories remains essential as new variants of such authorization flaws may emerge in future releases.