CVE-2026-121100
Description
An use after free flaw was found in the DOM 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 enforce control flow integrity to validate indirect call targets and prevent execution hijacking via dangling DOM pointers in the browser renderer: upgrade to Google Chrome 157.0.8103.38+ (or the fixed Chromium builds), which corrects memory lifetime management in the DOM component to resolve the use-after-free condition during HTML page processing, closing crafted HTML page. Until patched, this is a concern on all platforms running Chromium or Google Chrome browsers, so restrict user navigation to untrusted or external web pages and isolate web browsing sessions. As a compensating measure, enable ASLR to randomize memory layout and hinder gadget address resolution during exploitation, enforce NX/XD bit non-executable memory to prevent direct code execution from reused DOM memory allocations, compile binaries with Full RELRO and PIE to prevent global offset table overwrites, maintain SELinux in enforcing mode to confine the Chromium process and limit post-exploitation access, and deploy an EDR agent to monitor process behavior and detect anomalous child processes or shell spawning. These controls limit blast radius and contain exploitation, but they do not fix the underlying DOM use-after-free defect — apply the upstream patch to fully remediate.
Highest-impact CME: CME-301 SELinux (Enforcing Mode) (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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