CVE-2026-18012
Summary
by MITRE • 07/30/2026
Use after free in PDFium in Google Chrome prior to 151.0.7922.72 allowed a remote attacker to execute arbitrary code inside a sandbox via a crafted PDF file. (Chromium security severity: Low)
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Analysis
by VulDB Data Team • 07/30/2026
This vulnerability represents a critical use-after-free flaw in the PDFium library component that powers Chrome's built-in PDF rendering capabilities. The issue manifests when the browser processes maliciously crafted PDF files, specifically exploiting improper memory management during object deallocation. When a PDF document contains specially constructed elements that trigger certain rendering paths, the PDFium parser fails to properly track object references, leading to scenarios where freed memory regions are accessed after being reallocated for other purposes. This fundamental memory safety issue creates a pathway for remote code execution within Chrome's sandboxed environment.
The technical implementation of this vulnerability stems from inadequate reference counting mechanisms and improper object lifecycle management within the PDFium rendering engine. Attackers can construct PDF files that manipulate the parser into freeing memory structures while references to those structures still exist in the parsing stack or rendering pipeline. When subsequent operations attempt to access these freed objects, they encounter dangling pointers that may have been overwritten with attacker-controlled data. The Chromium security severity classification of low belies the actual risk, as this vulnerability can be exploited remotely without user interaction, requiring only the mere act of opening a malicious PDF file in Chrome.
The operational impact extends beyond simple code execution, as successful exploitation allows attackers to bypass Chrome's sandboxing mechanisms through sophisticated attack chains that leverage memory corruption primitives. This vulnerability affects all versions prior to 151.0.7922.72 and demonstrates the persistent challenges in securing complex PDF rendering engines that must handle billions of possible document structures while maintaining memory safety. The flaw aligns with CWE-416, which specifically addresses use-after-free conditions, and maps to attack techniques in the ATT&CK framework under T1059 for command and control execution, as well as T1203 for exploitation of remote services through browser components.
Mitigation strategies focus on immediate patch deployment across all affected Chrome versions, with additional defensive measures including enhanced sandbox configurations and stricter PDF parsing validation. Organizations should implement automated update mechanisms to ensure rapid deployment of security patches, while network administrators can consider implementing PDF content filtering solutions that scan documents before they reach end-user browsers. The vulnerability highlights the importance of regular security audits for browser components and demonstrates how seemingly minor memory management issues can lead to significant remote execution capabilities in modern web browsers.