CVE-2026-118336
Description
An improper input validation flaw was found in the Headless 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 (2026-11-03) ---
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 restrict Headless Chromium rendering processes from processing untrusted HTML content or isolate browser processes inside containerized sandboxes: upgrade to Google Chrome 156.0.8078.73 (or the fixed Chromium builds), which validates input in the Headless component to prevent arbitrary code execution inside the browser sandbox, closing crafted HTML page. Until patched, this is a concern on deployments running Chromium or Google Chrome in headless mode processing web content, so prevent Headless Chromium instances from loading or rendering untrusted, attacker-controlled HTML pages in automated workflows. As a compensating measure, enforce Landlock filesystem sandboxing to restrict process-level filesystem access for sandboxed browser processes, use gVisor runtime or syscall interception to isolate the headless browser execution environment from the host, apply systemd service sandboxing directives such as ProtectSystem and PrivateTmp when running Headless Chromium as a service, deploy an EDR agent to monitor process activity and detect unexpected binary execution or post-exploitation behavior, use Falco or eBPF runtime security to detect anomalous syscalls, process spawns, and network activity, and ensure ASLR is enabled across systems to hinder shellcode execution and ROP chain construction. These controls limit blast radius and contain exploitation, but they do not fix the underlying improper input validation defect — apply the upstream patch to fully remediate.
Highest-impact CME: CME-506 Landlock LSM (Filesystem Sandboxing) (medium)
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory)
An attacker could provide unexpected values and cause a program crash or arbitrary control of resource allocation, leading to excessive consumption of resources such as memory and CPU.
Confidentiality
Technical Impact: Read Memory; Read Files or Directories
An attacker could read confidential data if they are able to control resource references.
Integrity,Confidentiality,Availability
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
An attacker could use malicious input to modify data or possibly alter control flow in unexpected ways, including arbitrary command execution.
Frequently Asked Questions
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