CVE-2021-4052 in Chrome
Summary
by MITRE • 12/23/2021
Use after free in web apps in Google Chrome prior to 96.0.4664.93 allowed an attacker who convinced a user to install a malicious extension to potentially exploit heap corruption via a crafted Chrome Extension.
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Analysis
by VulDB Data Team • 06/22/2026
This vulnerability represents a critical use-after-free condition affecting google chrome versions prior to 96.0.4664.93 which could be exploited by malicious extensions to achieve heap corruption. The flaw occurs within the chrome extension system where improper memory management allows an attacker to manipulate freed memory locations through crafted extension code. This particular vulnerability falls under the common weakness enumeration category of CWE-416 which specifically addresses use-after-free conditions. The attack vector requires social engineering to convince a user to install a malicious extension, making it particularly dangerous in environments where users may not be security-aware. The technical implementation involves chrome's extension loading mechanism failing to properly validate or manage memory references after extension components have been destroyed, creating opportunities for attackers to overwrite or corrupt heap memory structures. When exploited, this vulnerability allows attackers to potentially execute arbitrary code with the privileges of the chrome browser process, which could lead to complete system compromise. The operational impact extends beyond simple memory corruption as it provides a pathway for privilege escalation and persistent access to the victim's system. This vulnerability aligns with several attack techniques documented in the attack tree framework including privilege escalation through memory corruption and malicious extension delivery. The exploitation typically involves crafting a malicious extension that triggers the use-after-free condition during extension lifecycle management, potentially allowing attackers to inject shellcode or establish reverse connections. Organizations should prioritize immediate patching of chrome installations to address this vulnerability, as the attack requires only user interaction to install a malicious extension rather than complex exploit chains. The remediation approach involves updating to chrome version 96.0.4664.93 or later where the memory management issues have been resolved through proper reference counting and memory validation mechanisms. Security teams should also implement extension review processes and user education programs to reduce the likelihood of successful social engineering attacks that could deliver malicious extensions. Additional mitigations include browser hardening measures such as sandboxing enforcement and strict extension permission controls to limit the potential impact of any successful exploitation attempts. This vulnerability demonstrates the critical importance of proper memory management in browser environments where extensions can potentially execute with elevated privileges and access system resources. The presence of such vulnerabilities in browser ecosystems highlights the ongoing challenge of maintaining secure software in complex multi-layered applications where memory corruption can lead to complete system compromise.