CVE-2026-118345
Description
An use after free flaw was found in the PDFium 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 enforce forward-edge control flow integrity to prevent hijacking vtable or function pointers through freed PDFium objects: upgrade to Chromium 156.0.8078.73 (or the fixed Chromium builds), which corrects object lifecycle management in the PDFium component to prevent use-after-free conditions, closing crafted HTML page. Until patched, this is a concern on users navigating to untrusted websites or opening untrusted HTML documents in Chromium across all platforms, so restrict user browsing to trusted websites and prevent opening untrusted HTML files. As a compensating measure, enable Address Space Layout Randomization to randomize process memory and hinder execution flow redirection, enforce non-executable memory via NX/XD bit on heap and data pages to block injected shellcode execution, compile with Full RELRO and Position Independent Executables to randomize base addresses and keep the Global Offset Table read-only, and deploy endpoint detection and response agents to monitor browser sandbox activity and intercept abnormal child processes. 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-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.
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