CVE-2026-121071
Description
An incorrect authorization flaw was found in the FileSystem component of the Chromium browser.
Upstream bug(s):
Statement
Red Hat Product Security rates the severity of this flaw as determined by the Google Chrome Security Advisory.
Mitigation
--- CME Mitigation Guidance (2026-11-04) ---
Disclaimer: The following mitigation solutions are provided as a courtesy, pending the application of an official patch. This content was generated utilizing AI tools in conjunction with data from https://cmetaxonomy.org. Customers are advised to independently evaluate and test these temporary mitigations within their own infrastructure.
The highest-value action is to confine browser filesystem operations to an isolated virtual filesystem or strict directory allowlist to prevent access outside intended boundaries: upgrade to Google Chrome 157.0.8103.38+ (or the fixed Chromium builds), which corrects authorization checks within the FileSystem component to prevent unauthorized file access and sandbox escape, closing all 2 injection vectors (crafted HTML page, social engineering). Until patched, this is a concern on Chromium browser deployments on any platform where users can access untrusted web content, so warn users against visiting untrusted or unverified websites and falling for social engineering lures that require interaction on crafted HTML pages. As a compensating measure, apply Landlock LSM unprivileged filesystem confinement to browser processes to restrict host path access, isolate browser processes within dedicated user and mount Linux namespaces to enforce sandbox boundaries, deploy EDR monitoring to detect anomalous process spawning or post-exploitation execution escaping the browser sandbox, and monitor with Falco or eBPF runtime security rules for unauthorized file access or anomalous executions outside expected browser profiles. These controls limit blast radius and contain exploitation, but they do not fix the underlying incorrect authorization defect — apply the upstream patch to fully remediate.
Highest-impact CME: CME-1303 Application-Level Filesystem Access Confinement (high)
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data; Read Files or Directories
An attacker could bypass intended access restrictions to read sensitive data, either by reading the data directly from a data store that is not correctly restricted, or by accessing insufficiently-protected, privileged functionality to read the data.
Integrity
Technical Impact: Modify Application Data; Modify Files or Directories
An attacker could bypass intended access restrictions to modify sensitive data, either by writing the data directly to a data store that is not correctly restricted, or by accessing insufficiently-protected, privileged functionality to write the data.
Access Control
Technical Impact: Gain Privileges or Assume Identity; Bypass Protection Mechanism
An attacker could bypass intended access restrictions to gain privileges by modifying or reading critical data directly, or by accessing privileged functionality.
Confidentiality,Integrity,Availability
Technical Impact: Execute Unauthorized Code or Commands
An attacker could use elevated privileges to execute unauthorized commands or code.
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
An attacker could gain unauthorized access to resources on the system and excessively consume those resources, leading to a denial of service.
Frequently Asked Questions
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