CVE-2023-35828 in Linux
Summary
by MITRE • 06/19/2023
An issue was discovered in the Linux kernel before 6.3.2. A use-after-free was found in renesas_usb3_remove in drivers/usb/gadget/udc/renesas_usb3.c.
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Analysis
by VulDB Data Team • 01/11/2026
The vulnerability identified as CVE-2023-35828 represents a critical use-after-free flaw within the Linux kernel's USB gadget driver implementation. This issue affects systems running Linux kernel versions prior to 6.3.2 and specifically resides in the renesas_usb3_remove function located at drivers/usb/gadget/udc/renesas_usb3.c. The flaw manifests during the removal process of USB gadget devices, creating a scenario where memory that has already been freed is accessed, potentially leading to arbitrary code execution or system instability.
The technical root cause of this vulnerability stems from improper memory management within the USB gadget driver for Renesas USB3 controllers. When the renesas_usb3_remove function is invoked to clean up resources associated with a USB gadget device, the driver fails to properly handle reference counting or memory deallocation sequences. This allows an attacker to potentially manipulate the device removal process in such a way that freed memory structures are accessed after deallocation, creating a classic use-after-free condition that can be exploited to execute malicious code with kernel-level privileges.
From an operational perspective, this vulnerability poses significant risks to embedded systems, servers, and devices that utilize Renesas USB3 controllers in gadget mode. The exploitation of this flaw could enable attackers to gain full kernel-level access, potentially leading to complete system compromise, data exfiltration, or persistent backdoor installation. Systems running affected kernel versions are particularly vulnerable when they handle USB gadget operations, making this issue especially concerning for IoT devices, embedded systems, and server environments where USB gadget functionality is utilized.
The vulnerability aligns with CWE-416, which specifically addresses use-after-free conditions in software development, and represents a critical weakness in the kernel's memory management subsystem. From an attacker's perspective, this flaw maps to the ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation could enable arbitrary code execution with kernel privileges. Organizations should prioritize immediate patching of affected systems to mitigate this risk, as the exploitation of use-after-free vulnerabilities often requires minimal prerequisites and can lead to complete system compromise.
Mitigation strategies should include immediate deployment of kernel updates to version 6.3.2 or later, which contain the necessary fixes for this memory management issue. System administrators should also implement monitoring for unusual USB gadget behavior or device removal patterns that might indicate exploitation attempts. Additionally, organizations should consider implementing kernel lockdown mechanisms and restricting USB gadget functionality where possible to reduce the attack surface. Regular security assessments and vulnerability scanning should be conducted to identify any remaining instances of affected kernel versions within the organization's infrastructure.
The impact of this vulnerability extends beyond immediate exploitation potential to encompass broader security implications for Linux-based systems relying on USB gadget functionality. The flaw demonstrates the importance of rigorous code review processes for kernel-level memory management and highlights the critical need for maintaining up-to-date system firmware and kernel versions. Security teams should also implement proper incident response procedures to detect and respond to potential exploitation attempts, as the use-after-free nature of this vulnerability makes it particularly difficult to detect through conventional security monitoring approaches.