CVE-2022-50065 in Linux
Summary
by MITRE • 06/18/2025
In the Linux kernel, the following vulnerability has been resolved:
virtio_net: fix memory leak inside XPD_TX with mergeable
When we call xdp_convert_buff_to_frame() to get xdpf, if it returns NULL, we should check if xdp_page was allocated by xdp_linearize_page(). If it is newly allocated, it should be freed here alone. Just like any other "goto err_xdp".
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Analysis
by VulDB Data Team • 11/30/2025
The vulnerability identified as CVE-2022-50065 represents a memory leak within the Linux kernel's virtio network driver implementation, specifically affecting the XDP_TX (eXpress Data Path transmit) functionality. This issue occurs in the virtio_net subsystem which handles virtualized network interfaces in virtualized environments. The flaw manifests when processing network packets through the XDP framework, which is designed for high-performance packet processing and is commonly used in network virtualization scenarios. The vulnerability is particularly significant because it affects the memory management within the transmit path of virtualized network devices, potentially leading to resource exhaustion over time.
The technical root cause of this vulnerability lies in improper memory deallocation logic within the virtio_net driver's XDP_TX implementation. When the function xdp_convert_buff_to_frame() fails to create an xdp frame structure and returns NULL, the code fails to properly check whether the underlying xdp_page was allocated through the xdp_linearize_page() function. This allocation occurs when network packets need to be linearized for processing, which is a common requirement in virtualized environments where packet data might be scattered across multiple memory pages. The missing check means that when the function fails, newly allocated xdp_page memory is not freed, creating a memory leak that accumulates with each failed packet processing attempt.
The operational impact of this memory leak extends beyond simple resource waste, as it can lead to progressive system degradation and potential denial of service conditions in virtualized environments. In high-throughput scenarios where virtual machines process large volumes of network traffic, this leak can accumulate to consume significant amounts of system memory over time. The vulnerability affects systems running Linux kernels that implement virtio_net with XDP support, particularly those using virtualization platforms such as KVM or Xen where virtual network interfaces are commonly deployed. Network administrators and cloud providers managing virtualized infrastructure are particularly at risk since the leak occurs in the core networking path, potentially affecting multiple virtual machines sharing the same host resources.
This vulnerability aligns with CWE-401 (Improper Release of Memory Before Removing Last Reference) and demonstrates weaknesses in resource management within kernel space code. The flaw also relates to ATT&CK technique T1499.001 (Network Denial of Service) as it can contribute to system resource exhaustion that affects network availability. The memory leak is particularly concerning in containerized environments where multiple virtual machines or containers might be sharing the same physical host resources, as it can cascade into broader system performance issues. Mitigation strategies include applying the kernel patch that implements proper memory deallocation checks, ensuring that xdp_page memory is freed when xdp_convert_buff_to_frame() fails, and monitoring system memory usage in virtualized environments to detect potential resource exhaustion scenarios.
The fix for this vulnerability requires careful attention to the memory management flow within the XDP_TX path. The solution involves adding a conditional check to determine if the xdp_page was allocated through xdp_linearize_page() and, if so, freeing it appropriately before returning NULL from xdp_convert_buff_to_frame(). This approach follows the established pattern of error handling within the kernel codebase where similar cleanup operations are performed in error paths. The fix ensures that memory allocated for packet processing is properly released regardless of whether the operation succeeds or fails, maintaining proper resource utilization in virtualized network environments. The patch demonstrates the importance of thorough error handling in kernel space code where resource management directly impacts system stability and performance.
Organizations running virtualized infrastructure should prioritize applying this kernel update as it addresses a fundamental memory management issue that could lead to system instability. The vulnerability is particularly relevant for cloud service providers and enterprise environments that heavily utilize virtualization technologies and XDP for network performance optimization. Regular monitoring of system memory consumption and network performance metrics becomes crucial for early detection of resource exhaustion scenarios that might be related to this vulnerability. The fix exemplifies the ongoing challenges in kernel security where seemingly small memory management issues can have significant operational impacts in complex virtualized environments.