CVE-2023-53125 in Linux
Summary
by MITRE • 05/02/2025
In the Linux kernel, the following vulnerability has been resolved:
net: usb: smsc75xx: Limit packet length to skb->len
Packet length retrieved from skb data may be larger than the actual socket buffer length (up to 9026 bytes). 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 • 11/10/2025
The vulnerability identified as CVE-2023-53125 affects the Linux kernel's USB network driver implementation, specifically within the smsc75xx driver component that manages ethernet controllers. This flaw represents a classic buffer overread condition that can lead to information disclosure through kernel memory leakage. The vulnerability manifests when processing network packets through USB-based ethernet adapters, creating a scenario where packet length metadata becomes inconsistent with actual data boundaries within the socket buffer structure.
The technical root cause stems from improper validation of packet length parameters during network packet processing within the USB ethernet driver subsystem. When packets are received through USB connections, the driver extracts length information from the packet data itself rather than verifying it against the actual socket buffer boundaries. This discrepancy allows for packet length values to exceed the legitimate data boundaries of the socket buffer, creating a situation where kernel memory beyond the intended packet data may be accessed and potentially exposed. The vulnerability specifically impacts the smsc75xx driver which handles various USB-to-ethernet adapters manufactured by SMSC (now Microchip Technology), making it relevant to numerous embedded systems and network appliances that utilize this hardware.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can potentially enable attackers to extract sensitive kernel memory contents including cryptographic keys, network credentials, or other confidential data structures. When a cloned socket buffer is passed up through the network stack, the oversized packet length field causes the kernel to read beyond the allocated buffer boundaries, resulting in memory leakage that could contain previously processed data from other network communications or kernel structures. This type of information disclosure vulnerability aligns with CWE-128, which describes "Wraparound Error" conditions where operations are performed on data that exceeds expected boundaries, and can be categorized under ATT&CK technique T1005 for data from local system.
Mitigation strategies for CVE-2023-53125 focus on implementing proper bounds checking within the smsc75xx driver's packet processing logic. The primary fix involves ensuring that packet length values are validated against the actual socket buffer length before any packet processing occurs, preventing the use of potentially oversized length parameters. System administrators should prioritize applying kernel updates that contain the patched driver implementation, which typically includes additional validation routines to limit packet lengths to the actual socket buffer capacity. Organizations utilizing USB ethernet adapters should also consider network segmentation and monitoring to detect anomalous packet behavior that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper input validation in kernel drivers and highlights the need for comprehensive testing of network stack components that handle external data inputs through USB interfaces.