CVE-2020-6436 in Chrome
Summary
by MITRE
Use after free in window management in Google Chrome prior to 81.0.4044.92 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.
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Analysis
by VulDB Data Team • 05/09/2025
The vulnerability identified as CVE-2020-6436 represents a critical use-after-free flaw within Google Chrome's window management subsystem that existed prior to version 81.0.4044.92. This type of vulnerability occurs when a program continues to reference memory locations after they have been freed, creating opportunities for memory corruption that can be exploited by remote attackers. The flaw specifically affects Chrome's handling of window management operations, which are fundamental components of the browser's user interface and rendering engine. The vulnerability's classification as a use-after-free aligns with CWE-416, which specifically addresses the reuse of memory after it has been freed, making it a well-documented and dangerous class of memory safety issue.
The technical exploitation of this vulnerability involves a remote attacker crafting a malicious HTML page that triggers the flawed window management code path. When Chrome processes such a page, the browser's window management system creates and subsequently frees memory structures that are then accessed again through the crafted page's JavaScript or DOM manipulation techniques. This memory corruption can lead to arbitrary code execution in the context of the browser's renderer process, potentially allowing attackers to bypass security boundaries and execute malicious payloads on the victim's system. The flaw demonstrates how seemingly benign user interface components can become attack vectors when memory management is improperly handled.
The operational impact of CVE-2020-6436 extends beyond simple browser exploitation, as it represents a significant vector for remote code execution attacks. Attackers could leverage this vulnerability to install malware, steal user data, or perform phishing attacks without requiring user interaction beyond visiting a malicious website. The vulnerability's presence in the window management subsystem means it could affect various browser operations including tab management, window resizing, and other UI interactions. This makes it particularly dangerous as it could be triggered through normal browsing activities, making detection and prevention more challenging for end users and security teams alike. The vulnerability's exploitation pathway aligns with ATT&CK technique T1059.007, which covers scripting through web-based interfaces.
Mitigation strategies for this vulnerability primarily involve updating to Google Chrome version 81.0.4044.92 or later, which includes patches that address the memory management issues in the window management subsystem. Organizations should implement comprehensive patch management processes to ensure timely deployment of security updates across all browser installations. Additionally, browser hardening techniques such as enabling sandboxing, disabling unnecessary browser features, and implementing content security policies can provide additional defense layers. Network-based protections including web application firewalls and intrusion detection systems can help detect and block exploitation attempts targeting this vulnerability. The remediation approach should also consider implementing user education programs to raise awareness about the risks of visiting untrusted websites and the importance of keeping browser software updated. Security monitoring should include detection of unusual browser behavior patterns that might indicate exploitation attempts, particularly around memory allocation and deallocation operations.