Understanding CVE-2024-27405: A Critical Vulnerability in Linux Kernel USB Gadget Subsystem

Welcome to our detailed analysis of CVE-2024-27405, a high-severity vulnerability identified in the Linux kernel. This issue, which scored 7.5, affects the 'usb: gadget: ncm' section of the Linux kernel, particularly when interacting with devices using the Network Control Model (NCM). This is crucial for Linux users who rely on USB gadgets for tethering, especially with a Windows 11 host.

To understand the severity and technical nuances of CVE-2024-27405, it is essential to delve into the functionality of the affected software. The Linux kernel’s 'usb: gadget: ncm' module is responsible for managing USB gadgets that use the Network Control Model (NCM). This includes ensuring efficient data transfer between devices, which is critical for applications such as tethering.

Issue Overview:

The vulnerability arises from a malfunction in the manner the NCM transfers data blocks (NTBs). Occasionally, when tethering over NCM with a Windows 11 host, an extra byte can be appended at the end of a correctly formatted NTB. While this might seem minor, the Linux kernel's processing logic incorrectly assumes this extra byte signifies the start of a new NTB, leading to the potential parsing of a faulty or corrupt NTB. Resultingly, all correctly parsed datagrams from the first NTB are dropped, causing data loss and potential disruptions in connectivity.

Detailed logs and traces reveal that when a transfer completes with an expected length but includes an extra byte, the system's handling mechanism fails to appropriately manage the data, mistaking it for a new, valid NTB. This misinterpretation leads to significant data handling errors and, in effect, impacts the reliability of data transfers over USB tethering.


The implications of not addressing this vulnerability are substantial. Users might experience intermittent connectivity issues, delayed data transfers, or complete failure of the tethering feature through NCM. For organizations that rely heavily on mobile connections for their operations, ignoring such a vulnerability could lead to operational disruptions and compromise data integrity.

Resolution and Patching:

Fortunately, patches are available. The resolution involves modifying the kernel's handling of these NTBs to ensure that any leftover bytes after a legitimate NTB are correctly identified and ignored if they do not constitute a valid NTB. This prevents the incorrect parsing and ensures that data integrity is maintained through the communication process.

Linux users are strongly advised to update to the latest version of the kernel that includes the patch for CVE-2024-27405. Delaying this update could leave your system vulnerable to the issues described.


CVE-2024-27405 highlights a critical aspect of system maintenance and security—keeping systems updated to avoid vulnerabilities that could disrupt operations. For Linux users, this is a reminder of the need to stay vigilant and up-to-date with system patches.

If you need help with patch management or ensuring that your Linux servers are protected against vulnerabilities like CVE-2024-27405, visit LinuxPatch, a streamlined patch management platform for Linux servers. Secure your systems now and prevent future disruptions.