CVE-2024-26328 in QEMU
Summary
by MITRE • 02/19/2024
An issue was discovered in QEMU 7.1.0 through 8.2.1. register_vfs in hw/pci/pcie_sriov.c does not set NumVFs to PCI_SRIOV_TOTAL_VF, and thus interaction with hw/nvme/ctrl.c is mishandled.
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Analysis
by VulDB Data Team • 07/25/2025
The vulnerability identified as CVE-2024-26328 resides within the QEMU virtualization platform, specifically affecting versions between 7.1.0 and 8.2.1. This issue manifests in the PCIe SR-IOV (Single Root I/O Virtualization) implementation where the register_vfs function in the hw/pci/pcie_sriov.c file fails to properly initialize the NumVFs parameter to the PCI_SRIOV_TOTAL_VF constant. The flaw occurs at the intersection of PCIe SR-IOV subsystem and NVMe controller implementation, creating a critical misconfiguration that undermines virtual I/O virtualization capabilities. The vulnerability represents a direct violation of proper hardware virtualization state management and configuration initialization protocols.
The technical root cause stems from improper initialization of virtual function (VF) count parameters within the SR-IOV configuration process. When the register_vfs function fails to set NumVFs to PCI_SRIOV_TOTAL_VF, it creates a scenario where the virtualization layer cannot correctly enumerate or manage the virtual functions allocated to PCIe devices. This misconfiguration directly impacts the interaction between the PCIe SR-IOV subsystem and the NVMe controller implementation in hw/nvme/ctrl.c, leading to potential resource allocation failures and incorrect device state reporting. The flaw demonstrates a classic configuration management error that can be classified under CWE-704 as improper initialization of security-critical variables and CWE-755 as improper handling of exceptions or error conditions.
The operational impact of this vulnerability extends beyond simple functionality degradation to potentially enabling privilege escalation and denial of service conditions within virtualized environments. When virtual functions are not properly initialized, malicious actors could exploit the inconsistent state to manipulate virtual device configurations, potentially gaining unauthorized access to underlying physical resources or causing system instability. The vulnerability particularly affects virtualized environments where NVMe storage devices are configured with SR-IOV capabilities, creating a pathway for attackers to manipulate virtual I/O paths and potentially compromise the integrity of virtual machine isolation. This aligns with ATT&CK technique T1068 which involves the exploitation of system vulnerabilities for privilege escalation, and T1499 which covers the manipulation of virtual environments.
Mitigation strategies must address both immediate patching and architectural considerations to prevent similar configuration errors in virtualization components. Organizations should prioritize updating QEMU installations to versions beyond 8.2.1 where this vulnerability has been resolved. Additionally, implementing comprehensive virtualization security monitoring can help detect anomalous behavior in SR-IOV configurations that might indicate exploitation attempts. System administrators should conduct thorough inventory checks of all virtualized environments to identify instances running vulnerable QEMU versions, particularly those utilizing NVMe storage with SR-IOV enabled. The vulnerability highlights the importance of proper initialization sequences in virtualization stacks and underscores the need for rigorous testing of device configuration flows, especially in complex virtual I/O subsystems where multiple hardware abstraction layers interact. Security teams should also consider implementing network segmentation and access controls around virtualized storage environments to limit the potential impact of any exploitation attempts.