CVE-2026-97607 in Linux
Summary
by MITRE • 09/25/2026
In the Linux kernel, the following vulnerability has been resolved:
vdpa: ifcvf: Put device on unsupported feature error
Route unsupported provisioned features through the common error path after vdpa_alloc_device() so the allocated device and adapter pointer are released consistently.
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Analysis
by VulDB Data Team • 09/25/2026
The identified issue resides within the virtio-data-plane (vDPA) subsystem of the Linux kernel, specifically affecting the ifcvf driver which provides support for Intel CXL Virtual Function devices. This vulnerability manifests as a resource management flaw during the device initialization and feature negotiation phase. When a user or hypervisor attempts to provision specific features for a vDPA device that are not supported by the underlying hardware or driver implementation, the kernel fails to properly clean up previously allocated resources before returning an error code. The core technical defect lies in the control flow logic within the ifcvf probe and configuration routines. Upon detecting unsupported features, the execution path bypasses the standard cleanup sequence, leaving memory allocations for the device structure and adapter pointers unreleased. This constitutes a classic resource leak vulnerability where system resources are consumed but never returned to the operating system pool after an operation fails or is aborted due to invalid input parameters.
From a security and stability perspective, this flaw can lead to progressive degradation of system performance over time if triggered repeatedly. Each instance of attempting to configure unsupported features results in leaked kernel memory structures that remain allocated until the module is unloaded or the system is rebooted. In environments where vDPA devices are dynamically configured by virtualization managers such as QEMU or libvirt, an attacker with access to these management interfaces could potentially exploit this behavior through a denial-of-service vector. By continuously sending requests for unsupported feature sets, it is possible to exhaust available kernel memory resources, leading to system instability, application crashes, or complete host unavailability depending on the severity of the leak and the overall resource constraints of the environment. This aligns with CWE-401, which describes missing release of memory after effective usage, a common pattern in systems programming where error handling paths are often overlooked during initial development phases.
The operational impact extends beyond simple memory consumption to include potential complications in device state management. Since the adapter pointer and device structure remain allocated but potentially in an inconsistent or partially initialized state, subsequent attempts to interact with other devices on the same system might encounter unexpected behaviors if global counters or reference counts are affected by these orphaned allocations. While this is primarily a reliability issue rather than a direct privilege escalation vector, it undermines the robustness of the virtualization stack and violates principles of secure coding regarding proper resource lifecycle management. The vulnerability highlights the importance of rigorous error handling in kernel-space drivers where memory safety is not guaranteed by garbage collection mechanisms present in higher-level languages.
To mitigate this risk, the resolution involves refactoring the error handling logic within the ifcvf driver to ensure that all allocated resources are consistently released through a common cleanup path whenever feature negotiation fails or unsupported features are detected. This ensures that vdpa_alloc_device and associated adapter structures are properly freed regardless of whether the initialization succeeds or encounters an invalid configuration request. Administrators should apply kernel updates containing this fix as soon as they become available for their respective distributions. In the interim, limiting the scope of vDPA device configurations to only those features explicitly documented as supported by the hardware can reduce the likelihood of triggering the flawed code path. Furthermore, monitoring system memory usage and dmesg logs for signs of increasing kernel object counts may help in detecting instances where this leak is being actively exploited or occurring frequently due to misconfigured virtualization environments. This fix reinforces adherence to ATT&CK techniques related to resource exhaustion by closing a pathway that could otherwise be leveraged for such attacks, thereby enhancing the overall resilience of the Linux vDPA implementation against configuration-based abuse.