CVE-2023-53062 in Linux
Summary
by MITRE • 05/02/2025
In the Linux kernel, the following vulnerability has been resolved:
net: usb: smsc95xx: Limit packet length to skb->len
Packet length retrieved from descriptor may be larger than the actual socket buffer length. In such case the cloned skb passed up the network stack will leak kernel memory contents.
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Analysis
by VulDB Data Team • 11/07/2025
The vulnerability identified as CVE-2023-53062 affects the Linux kernel's USB networking driver implementation, specifically within the smsc95xx driver component that handles SMSC USB Ethernet adapters. This issue represents a classic buffer overflow condition that can lead to information disclosure through kernel memory leaks. The flaw exists in the network packet processing pipeline where the driver receives packet information from hardware descriptors and attempts to validate packet boundaries against socket buffer lengths. When packet length information from the hardware descriptor exceeds the actual socket buffer size, the driver fails to properly constrain the packet data, creating a scenario where kernel memory contents can be inadvertently exposed to user-space applications.
The technical root cause of this vulnerability stems from inadequate input validation within the USB network driver's packet handling logic. The smsc95xx driver retrieves packet length information directly from USB hardware descriptors without proper bounds checking against the actual socket buffer allocation. This discrepancy occurs during the packet cloning process where the driver creates copies of network packets for further processing in the kernel network stack. When the hardware descriptor reports a packet length that surpasses the allocated socket buffer space, the driver's packet processing routine fails to truncate or reject the oversized packet, allowing the kernel memory contents beyond the intended buffer boundaries to be included in the cloned packet structure.
This vulnerability operates at the network driver level within the Linux kernel's networking subsystem and can be classified under CWE-129 as "Improper Validation of Array Index" and CWE-787 as "Out-of-bounds Write." The operational impact extends beyond simple information disclosure as it represents a potential attack vector for kernel memory reconnaissance. An attacker could leverage this vulnerability to extract sensitive kernel memory contents including cryptographic keys, session tokens, or other confidential data that might be stored in adjacent memory regions. The vulnerability affects systems running Linux kernels with the smsc95xx USB Ethernet driver, particularly those utilizing SMSC USB network adapters in environments where network traffic monitoring or packet inspection capabilities are present.
The attack surface for this vulnerability is primarily limited to systems that utilize SMSC USB Ethernet adapters and have the smsc95xx driver loaded in the kernel. The exploitation requires network traffic to be processed through the affected driver, making it more relevant in scenarios where USB network interfaces are actively used for network communication. The vulnerability is particularly concerning in environments where kernel memory contains sensitive information and where attackers can influence network packet processing through legitimate network traffic. According to ATT&CK framework, this vulnerability aligns with T1005 as "Data from Local System" and T1552 as "Unsecured Credentials" since it enables unauthorized access to kernel memory contents that may contain sensitive data.
Mitigation strategies for CVE-2023-53062 involve applying the official kernel security patches released by the Linux kernel maintainers, which implement proper bounds checking between hardware descriptor packet lengths and actual socket buffer allocations. System administrators should ensure that all Linux systems utilizing SMSC USB network adapters are updated to kernel versions containing the fix, typically kernel versions 6.2.13, 6.3.2, or later depending on the specific kernel release line. Additionally, network administrators should monitor for unusual network traffic patterns that might indicate exploitation attempts, and consider implementing network segmentation to limit potential attack vectors. The fix implemented in the patched kernel versions enforces strict packet length validation during the skb cloning process, ensuring that packet data cannot exceed the allocated socket buffer boundaries and preventing kernel memory leakage through malformed packet length information from hardware descriptors.