CVE-2026-121129
Description
An use after free flaw was found in the WebRTC 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 and Shadow Call Stack to validate indirect call targets and prevent hijacked virtual table pointers from redirecting execution: upgrade to Chromium 157.0.8103.38+ (or the fixed Chromium builds), which resolves the use-after-free memory corruption condition within the WebRTC component, closing crafted HTML page. Until patched, this is a concern on Users running Chromium on any platform who browse untrusted web content, so Prevent users from accessing untrusted websites or loading untrusted HTML pages in Chromium. As a compensating measure, Enable Address Space Layout Randomization to impede reliable redirection of execution to injected payloads or ROP gadgets, Enforce NX/XD bit non-executable memory protections to prevent code execution from corrupted heap or data pages, Ensure full RELRO and PIE are enabled to protect Global Offset Table entries and randomize binary code offsets, and Deploy EDR agents to detect anomalous process behavior and payload execution originating from the browser renderer process. These controls limit blast radius and contain exploitation, but they do not fix the underlying WebRTC use-after-free defect — apply the upstream patch to fully remediate.
Highest-impact CME: CME-113 Control Flow Integrity (CFI / Shadow Call Stack) (high)
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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