CVE-2026-121076
Description
An use after free flaw was found in the WebXR 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 prevent use-after-free memory corruption and control flow hijacking in the Chromium WebXR component: upgrade to Google Chrome 157.0.8103.38 (or the fixed Chromium builds), which fixes use-after-free memory corruption in the WebXR component that allowed sandbox escape, closing crafted HTML page. Until patched, this is a concern on Chromium browser users across all platforms, so warn users against navigating to untrusted or suspicious HTML pages and restrict access to unknown web origins via web filtering. As a compensating measure, enable ASLR to randomize userspace memory addresses and impede pointer reuse during exploitation, enforce NX/XD bit non-executable memory to prevent execution of shellcode placed in heap regions, compile with Full RELRO and PIE to protect relocation tables and prevent function pointer overwrites, enable Control Flow Integrity or Shadow Call Stack to validate indirect call targets against virtual table corruption, and deploy EDR agents to detect abnormal browser subprocess spawning, memory injection, and post-exploitation sandbox escape activity. These controls limit blast radius and contain exploitation, but they do not fix the underlying use-after-free flaw — 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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