CVE-2020-6541 in Chrome
Summary
by MITRE
Use after free in WebUSB in Google Chrome prior to 84.0.4147.105 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.
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Analysis
by VulDB Data Team • 05/05/2025
The vulnerability CVE-2020-6541 represents a critical use-after-free flaw in Google Chrome's WebUSB implementation that existed prior to version 84.0.4147.105. This issue resides within the browser's handling of Universal Serial Bus device access through the WebUSB API, which allows websites to communicate with connected USB devices directly from the browser environment. The vulnerability manifests when a malicious website attempts to exploit the improper memory management within Chrome's WebUSB subsystem, creating conditions where freed memory blocks are still accessed by subsequent operations. This particular flaw falls under the CWE-416 category of Use After Free, which occurs when a program continues to reference memory after it has been freed, leading to unpredictable behavior and potential exploitation. The WebUSB API was designed to enable legitimate web applications to interact with USB devices, but the improper memory deallocation in Chrome's implementation created a pathway for attackers to manipulate the heap memory layout.
The operational impact of this vulnerability extends beyond simple memory corruption, as it provides remote attackers with a mechanism to potentially execute arbitrary code on affected systems. When a user visits a malicious webpage containing crafted HTML code, the attacker can trigger the use-after-free condition through carefully constructed WebUSB API calls that manipulate device handles and associated memory structures. The heap corruption that results from this vulnerability can be leveraged to achieve code execution, privilege escalation, or information disclosure depending on the specific exploitation techniques employed. Attackers typically exploit such vulnerabilities by controlling the heap layout to overwrite critical function pointers or vtable entries, effectively redirecting program execution flow. This vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter: PowerShell and T1068 for Exploitation for Privilege Escalation, as the heap corruption can be used to gain elevated privileges or execute malicious payloads. The vulnerability affects all Chrome versions prior to 84.0.4147.105, making it particularly dangerous as it impacted a large user base.
Mitigation strategies for CVE-2020-6541 primarily focus on immediate remediation through browser updates and implementing additional security controls. The most effective immediate fix is upgrading to Chrome version 84.0.4147.105 or later, where Google implemented proper memory management fixes for the WebUSB API. Organizations should also consider implementing Content Security Policy (CSP) headers to restrict WebUSB access from untrusted origins and disable USB device access for websites that do not require such functionality. Browser hardening measures including sandboxing and memory protection mechanisms should be enabled to limit the potential impact of successful exploitation attempts. Network-level controls such as web application firewalls can help detect and block malicious WebUSB API usage patterns. Additionally, security teams should monitor for indicators of compromise related to this vulnerability, including unusual USB device enumeration patterns or memory access violations. The vulnerability demonstrates the importance of proper memory management in browser components and highlights the risks associated with exposing low-level hardware interfaces through web APIs without adequate security controls. Organizations should also consider implementing user education programs to raise awareness about the risks of visiting untrusted websites and the potential for drive-by downloads through such vulnerabilities.