CVE-2026-86564 in Red Hat
Summary
by MITRE • 09/09/2026
A flaw was found in DPDK lib/vhost. Missing length validation before reading command_data in the virtio-net control-queue handler can cause an out-of-bounds read and a host process crash.
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability identified within the Data Plane Development Kit, specifically affecting the vhost library component, represents a critical security flaw rooted in improper input validation during network packet processing operations. The DPDK is widely utilized to provide high-performance user-space networking capabilities for virtualized environments and cloud infrastructure, making its integrity paramount for system stability and data confidentiality. In this specific instance, the defect resides within the virtio-net control-queue handler, which is responsible for managing administrative commands sent by guest virtual machines to the host vhost device emulation layer. The core technical issue involves a missing length validation check before the application attempts to read command_data from the provided buffer. This oversight means that if a malicious or compromised guest VM sends a control queue message with an incorrectly specified or excessively large length field, the handler will proceed to access memory locations beyond the allocated bounds of the input data structure without verifying whether those addresses are valid and within the permitted range.
This lack of boundary checking directly leads to an out-of-bounds read condition, which is classified under CWE-125 as Out-of-Bounds Read in standard vulnerability taxonomy. When the host process attempts to retrieve command parameters from memory locations that lie outside the intended buffer boundaries, it may inadvertently access sensitive information stored adjacent to the buffer in RAM. While the immediate manifestation described is a host process crash due to accessing invalid or protected memory pages, such out-of-bounds reads can also facilitate unauthorized data exfiltration if the accessed memory contains cryptographic keys, session tokens, or other confidential host-side state information. The severity of this vulnerability is amplified by its location within the control path of virtualized networking; an attacker with access to a guest VM that utilizes virtio-net devices over vhost-user sockets can exploit this flaw to disrupt service availability on the host system.
From an operational impact perspective, the primary consequence observed is denial of service through process termination. The crash of the DPDK-based application effectively halts network processing for all virtual machines relying on that specific instance or socket connection. In a multi-tenant cloud environment where vhost devices are shared across multiple workloads, this disruption can cascade into broader availability issues, affecting other tenants and potentially violating service level agreements regarding uptime and reliability. Furthermore, depending on the compiler optimizations and runtime memory layout, an out-of-bounds read might not always result in an immediate crash but could instead lead to unpredictable behavior or information leakage, complicating incident response efforts as the root cause may be obscured by subsequent application state corruption.
To mitigate this vulnerability, developers must implement rigorous input validation within the virtio-net control-queue handler prior to any memory access operations involving command_data. This includes verifying that the length field provided in the control message does not exceed the maximum allowed size for the specific command type and ensuring that the total buffer size is sufficient to contain all expected parameters. Patching involves updating the DPDK library to version where this validation logic has been corrected, thereby enforcing strict bounds checking on all incoming control queue messages from guest VMs. Additionally, system administrators should consider deploying defense-in-depth strategies such as enabling Address Space Layout Randomization and using memory protection features like SELinux or AppArmor to restrict the privileges of vhost processes, limiting the potential impact if an exploit is attempted. Regularly auditing network configurations for unnecessary exposure of vhost-user sockets and restricting access to these endpoints only to trusted guest VMs further reduces the attack surface associated with this class of vulnerabilities aligned with ATT&CK techniques involving resource hijacking or denial of service via application layer exploitation.