CVE-2024-26964 in Linux
Summary
by MITRE • 05/01/2024
In the Linux kernel, the following vulnerability has been resolved:
usb: xhci: Add error handling in xhci_map_urb_for_dma
Currently xhci_map_urb_for_dma() creates a temporary buffer and copies the SG list to the new linear buffer. But if the kzalloc_node() fails, then the following sg_pcopy_to_buffer() can lead to crash since it tries to memcpy to NULL pointer.
So return -ENOMEM if kzalloc returns null pointer.
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Analysis
by VulDB Data Team • 01/26/2026
The vulnerability identified as CVE-2024-26964 resides within the Linux kernel's USB subsystem, specifically in the xhci (eXtensible Host Controller Interface) driver implementation. This flaw represents a critical memory management issue that could lead to system instability and potential denial of service conditions. The vulnerability manifests in the xhci_map_urb_for_dma() function which handles the mapping of USB requests for direct memory access operations. The xhci driver serves as the foundation for USB 3.0 host controller implementations across numerous Linux systems, making this vulnerability particularly concerning for widespread impact.
The technical root cause of this vulnerability stems from inadequate error handling within the memory allocation process of the USB transfer mapping function. When xhci_map_urb_for_dma() attempts to create a temporary linear buffer using kzalloc_node() for copying scatter-gather list data, the function fails to properly validate the allocation result. If the memory allocation fails and returns a null pointer, subsequent operations attempt to copy data to this invalid memory location. This leads to a classic null pointer dereference scenario where sg_pcopy_to_buffer() tries to execute memcpy operations against a NULL destination pointer, resulting in immediate system crashes or kernel oops conditions.
This vulnerability directly maps to CWE-476, which describes NULL pointer dereference conditions in software implementations. The flaw demonstrates poor defensive programming practices where the kernel driver fails to implement proper error checking for critical memory allocation operations. From an operational perspective, this vulnerability represents a significant risk to Linux systems that rely on USB 3.0 functionality, particularly in server environments, embedded systems, and desktop configurations where USB devices are frequently connected and disconnected. The crash conditions could be exploited by malicious actors to perform denial of service attacks against systems, potentially affecting critical infrastructure deployments.
The operational impact of CVE-2024-26964 extends beyond simple system crashes, as it affects the fundamental USB subsystem reliability and could compromise system availability in environments where continuous USB operations are required. Systems utilizing USB 3.0 controllers with xhci drivers are particularly vulnerable, including desktop computers, servers, embedded devices, and mobile platforms running Linux distributions. The vulnerability is especially dangerous in automated environments where USB devices are frequently accessed or where USB-based system management interfaces are utilized. From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through resource exhaustion, as the memory allocation failure could be exploited to consume system resources and cause service disruption.
Mitigation strategies for this vulnerability involve applying the official kernel patch that implements proper error handling for the kzalloc_node() allocation failure case. The fix ensures that when memory allocation fails, the function returns -ENOMEM instead of proceeding with operations on invalid memory pointers. System administrators should prioritize updating their Linux kernel versions to include this patch, particularly in production environments where USB connectivity is essential. Additionally, monitoring systems should be configured to detect kernel oops or system crash events that may indicate exploitation attempts. Organizations should also consider implementing USB device access controls and monitoring to limit potential attack surfaces. The vulnerability serves as a reminder of the critical importance of proper error handling in kernel space code, particularly when dealing with memory allocation operations that form the foundation of system stability and security.