CVE-2026-121035
Description
An use after free flaw was found in the Prerender 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 disable or isolate prerendering of untrusted web content to prevent use-after-free exploitation escaping the browser sandbox: upgrade to Google Chrome 157.0.8103.38 (or the fixed Chromium builds), which resolves the use-after-free condition in the Prerender component to prevent arbitrary code execution outside the sandbox, closing crafted HTML page. Until patched, this is a concern on Chromium and Google Chrome users on all platforms navigating to untrusted web pages, so restrict browser navigation to untrusted external websites and prevent users from loading unverified links or web pages. As a compensating measure, Enforce Address Space Layout Randomization to randomize userspace process memory layouts and hinder reliable code execution, Enforce non-executable memory permissions across data and heap pages to block execution of injected shellcode, Apply Full RELRO and PIE to make relocation tables read-only and restrict memory overwrite targets, Enable Control Flow Integrity and Shadow Call Stack to validate indirect branch targets and prevent hijacking of corrupted function pointers, and Deploy Endpoint Detection and Response agents to monitor, detect, and intercept anomalous processes or shells spawned after a sandbox escape. These controls limit blast radius and contain exploitation, but they do not fix the underlying use-after-free defect — apply the upstream patch to fully remediate.
Highest-impact CME: CME-101 ASLR (Address Space Layout Randomization) (medium)
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory
The use of previously freed memory may corrupt valid data, if the memory area in question has been allocated and used properly elsewhere.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If chunk consolidation occurs after the use of previously freed data, the process may crash when invalid data is used as chunk information.
Confidentiality
Technical Impact: Read Memory
Read operations on freed memory can sometimes leak sensitive information instead of causing a crash
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If malicious data is entered before chunk consolidation can take place, it may be possible to take advantage of a write-what-where primitive to execute arbitrary code. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.
Frequently Asked Questions
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