CVE-2022-48949 in Linux
Summary
by MITRE • 10/21/2024
In the Linux kernel, the following vulnerability has been resolved:
igb: Initialize mailbox message for VF reset
When a MAC address is not assigned to the VF, that portion of the message sent to the VF is not set. The memory, however, is allocated from the stack meaning that information may be leaked to the VM. Initialize the message buffer to 0 so that no information is passed to the VM in this case.
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Analysis
by VulDB Data Team • 01/18/2026
The vulnerability identified as CVE-2022-48949 affects the Linux kernel's implementation of the igb driver, specifically addressing a security flaw in the virtual function (VF) reset handling mechanism. This issue resides within the Intel Gigabit Ethernet driver that manages network interfaces in virtualized environments. The vulnerability stems from improper initialization of mailbox communication buffers during VF reset operations, creating potential information disclosure risks that could compromise system security in virtualized deployments.
The technical flaw manifests when a virtual function lacks an assigned MAC address during the reset process. In this scenario, the driver fails to properly initialize the mailbox message buffer portion that would normally contain MAC address information. While memory allocation occurs on the stack for this buffer, the uninitialized memory contents are inadvertently transmitted to the virtual machine. This represents a classic information disclosure vulnerability where residual data from previous operations or kernel memory regions may be leaked to unauthorized entities within the virtualized environment.
The operational impact of this vulnerability extends beyond simple information leakage, as it creates potential attack vectors for malicious actors within virtualized networks. When a VM receives uninitialized memory contents through the mailbox communication channel, it may inadvertently process or expose sensitive data that was previously stored in those memory locations. This could include kernel memory contents, previous network packet data, or other confidential information that should not be accessible to the virtual machine. The vulnerability particularly affects environments using Intel's 82576 and 82580 series network adapters in virtualized configurations where multiple VMs share the same physical hardware resources.
This vulnerability aligns with CWE-248, which addresses "Uninitialized Variable," and represents a specific case where stack memory initialization fails in a security-sensitive context. From an attack perspective, it corresponds to techniques described in the MITRE ATT&CK framework under T1059.001 for Command and Scripting Interpreter, where attackers might exploit information disclosure to gain additional context about the target system. The issue demonstrates how seemingly benign initialization failures can create security implications in virtualized environments where memory isolation is critical for maintaining security boundaries between VMs.
The mitigation for this vulnerability requires updating to kernel versions that include the fix, which properly initializes the mailbox message buffer to zero before sending it to the virtual machine. This ensures that no residual data from previous operations or kernel memory contents is inadvertently exposed to the VM during VF reset operations. System administrators should prioritize applying this patch in virtualized environments where the igb driver is in use, particularly in cloud computing and data center deployments where multiple VMs may be sharing the same physical network hardware. The fix implements a defensive programming practice that prevents information leakage by ensuring all buffer contents are explicitly initialized before use, thereby maintaining proper security boundaries in virtualized network environments.